diff --git a/asset.py b/asset.py
index dd62caa..578de36 100644
--- a/asset.py
+++ b/asset.py
@@ -32,7 +32,7 @@ class Asset(SymbolMixin, ModelSQL, ModelView):
 
     name = fields.Function(fields.Char(
         string='Name', readonly=True),
-            'get_name_symbol', searcher='search_rec_name')
+        'get_name_symbol', searcher='search_rec_name')
     company = fields.Many2One(
         string='Company', model_name='company.company',
         required=True, ondelete="RESTRICT")
@@ -46,12 +46,9 @@ class Asset(SymbolMixin, ModelSQL, ModelView):
     uom = fields.Many2One(
         string='UOM', required=True, model_name='product.uom',
         ondelete='RESTRICT',
-        states={
-            'readonly': ~Bool(Eval('product')),
-        },
-        domain=[
-            ('category', '=', Eval('product_uom')),
-        ], depends=['product_uom', 'product'])
+        states={'readonly': ~Bool(Eval('product'))},
+        domain=[('category', '=', Eval('product_uom'))],
+        depends=['product_uom', 'product'])
     symbol = fields.Function(fields.Char(
         string='UOM', readonly=True), 'get_name_symbol',
         searcher='search_uom_symbol')
@@ -74,9 +71,7 @@ class Asset(SymbolMixin, ModelSQL, ModelView):
         model_name='currency.currency', ondelete='RESTRICT')
     currency_digits = fields.Integer(
         string='Digits', required=True,
-        domain=[
-            ('currency_digits', '>=', 0),
-            ('currency_digits', '<=', 6)])
+        domain=[('currency_digits', '>=', 0), ('currency_digits', '<=', 6)])
 
     wkn = fields.Function(fields.Char(
         string='NSIN', readonly=True,
@@ -112,9 +107,8 @@ class Asset(SymbolMixin, ModelSQL, ModelView):
         string='Select days', required=True, selection=sel_updtdays)
     updttime = fields.Time(
         string='Time',
-        states={
-            'readonly': ~Bool(Eval('updtsources')),
-        }, depends=['updtsources'])
+        states={'readonly': ~Bool(Eval('updtsources'))},
+        depends=['updtsources'])
     nextupdate = fields.Function(fields.DateTime(
         string='Next Update', readonly=True),
         'get_nextupdates', searcher='search_nextupdate')
@@ -201,7 +195,7 @@ class Asset(SymbolMixin, ModelSQL, ModelView):
                     'source': x[1],
                 } for x in records]
 
-            if len(to_create) > 0:
+            if to_create:
                 AssetSourceRel.create(to_create)
             asset_table.drop_column('updtsource')
 
@@ -262,7 +256,7 @@ class Asset(SymbolMixin, ModelSQL, ModelView):
     def on_change_updtsources(self):
         """ clear time-fields
         """
-        if len(self.updtsources) == 0:
+        if not self.updtsources:
             self.updttime = None
         else:
             self.updttime = time(11, 30)
@@ -423,8 +417,7 @@ class Asset(SymbolMixin, ModelSQL, ModelView):
 
         query = tab_query.select(
                 tab_query.id,
-                where=Operator(tab_query.date, clause[2]),
-            )
+                where=Operator(tab_query.date, clause[2]))
         return [('id', 'in', query)]
 
     @classmethod
@@ -436,8 +429,7 @@ class Asset(SymbolMixin, ModelSQL, ModelView):
 
         query = tab_query.select(
                 tab_query.id,
-                where=Operator(tab_query.rate, clause[2]),
-            )
+                where=Operator(tab_query.rate, clause[2]))
         return [('id', 'in', query)]
 
     @staticmethod
@@ -449,8 +441,7 @@ class Asset(SymbolMixin, ModelSQL, ModelView):
 
         query = tab_query.select(
                 tab_query.date,
-                where=tab_query.id == table.id,
-            )
+                where=tab_query.id == table.id)
         return [query]
 
     @staticmethod
@@ -462,8 +453,7 @@ class Asset(SymbolMixin, ModelSQL, ModelView):
 
         query = tab_query.select(
                 tab_query.rate,
-                where=tab_query.id == table.id,
-            )
+                where=tab_query.id == table.id)
         return [query]
 
     @classmethod
@@ -489,8 +479,7 @@ class Asset(SymbolMixin, ModelSQL, ModelView):
                 tab_rate1.rate,
                 distinct_on=[tab_rate1.asset],
                 order_by=[tab_rate1.asset, tab_rate1.date.desc],
-                where=where_asset,
-            )
+                where=where_asset)
 
         days_diff = days + 5
         query = tab_today.join(
@@ -506,8 +495,7 @@ class Asset(SymbolMixin, ModelSQL, ModelView):
                 (tab_today.rate * 100.0 / NullIf(tab_rate2.rate, 0.00) -
                     100.0).as_('percent'),
                 distinct_on=[tab_today.id],
-                order_by=[tab_today.id, tab_rate2.date.desc]
-            )
+                order_by=[tab_today.id, tab_rate2.date.desc])
         return query
 
     @staticmethod
@@ -520,8 +508,7 @@ class Asset(SymbolMixin, ModelSQL, ModelView):
 
         query = tab_asset.select(
                 tab_asset.percent,
-                where=tab_asset.id == table.id,
-            )
+                where=tab_asset.id == table.id)
         return [query]
 
     @staticmethod
@@ -534,8 +521,7 @@ class Asset(SymbolMixin, ModelSQL, ModelView):
 
         query = tab_asset.select(
                 tab_asset.percent,
-                where=tab_asset.id == table.id,
-            )
+                where=tab_asset.id == table.id)
         return [query]
 
     @staticmethod
@@ -548,8 +534,7 @@ class Asset(SymbolMixin, ModelSQL, ModelView):
 
         query = tab_asset.select(
                 tab_asset.percent,
-                where=tab_asset.id == table.id,
-            )
+                where=tab_asset.id == table.id)
         return [query]
 
     @staticmethod
@@ -562,8 +547,7 @@ class Asset(SymbolMixin, ModelSQL, ModelView):
 
         query = tab_asset.select(
                 tab_asset.percent,
-                where=tab_asset.id == table.id,
-            )
+                where=tab_asset.id == table.id)
         return [query]
 
     @staticmethod
@@ -576,8 +560,7 @@ class Asset(SymbolMixin, ModelSQL, ModelView):
 
         query = tab_asset.select(
                 tab_asset.percent,
-                where=tab_asset.id == table.id,
-            )
+                where=tab_asset.id == table.id)
         return [query]
 
     @classmethod
@@ -619,14 +602,13 @@ class Asset(SymbolMixin, ModelSQL, ModelView):
                         'change_month6': 180,
                         'change_month12': 365,
                         }[x],
-                    asset_ids=asset_id_lst,
-                    )
+                    asset_ids=asset_id_lst)
                 cursor.execute(*tab_percent)
                 records = cursor.fetchall()
 
                 for record in records:
                     result[x][record[0]] = record[3].quantize(exp) \
-                            if record[3] is not None else None
+                        if record[3] is not None else None
         return result
 
     @classmethod
@@ -660,8 +642,7 @@ class Asset(SymbolMixin, ModelSQL, ModelView):
                 tab_asset.updtdays,
                 tab_asset.updttime,
                 distinct_on=[tab_asset.id],
-                order_by=[tab_asset.id, tab_rate.date.desc],
-            )
+                order_by=[tab_asset.id, tab_rate.date.desc])
 
         query = tab_date.select(
             tab_date.id,
@@ -673,8 +654,7 @@ class Asset(SymbolMixin, ModelSQL, ModelView):
                     (Extract('dow', tab_date.date) == 6),
                     tab_date.date + Literal(2)),
                 else_=tab_date.date,
-                ) + tab_date.updttime).as_('updttime'),
-            )
+                ) + tab_date.updttime).as_('updttime'))
         return query
 
     @classmethod
@@ -688,8 +668,7 @@ class Asset(SymbolMixin, ModelSQL, ModelView):
         query = tab_updt.select(
                 tab_updt.id,
                 tab_updt.updttime,
-                where=tab_updt.id.in_([x.id for x in assets]),
-            )
+                where=tab_updt.id.in_([x.id for x in assets]))
         cursor.execute(*query)
         records = cursor.fetchall()
 
@@ -713,8 +692,7 @@ class Asset(SymbolMixin, ModelSQL, ModelView):
 
         query = tab_updt.select(
                 tab_updt.id,
-                where=Operator(tab_updt.updttime, clause[2]),
-            )
+                where=Operator(tab_updt.updttime, clause[2]))
         return [('id', 'in', query)]
 
     @classmethod
@@ -751,8 +729,7 @@ class Asset(SymbolMixin, ModelSQL, ModelView):
                 tab_asset.id,
                 tab_wkn.code.as_('wkn'),
                 tab_secsymb.code.as_('secsymb'),
-                tab_isin.code.as_('isin'),
-            )
+                tab_isin.code.as_('isin'))
         return query
 
     @staticmethod
@@ -776,8 +753,7 @@ class Asset(SymbolMixin, ModelSQL, ModelView):
                 condition=tab_templ.id == tab_prod.template
             ).select(
                 tab_templ.name,
-                where=tab_asset.id == table.id
-            )
+                where=tab_asset.id == table.id)
         return [query]
 
     @staticmethod
@@ -790,8 +766,7 @@ class Asset(SymbolMixin, ModelSQL, ModelView):
 
         query = tab_ids.select(
                 getattr(tab_ids, 'wkn'),
-                where=tab_ids.id == table.id,
-            )
+                where=tab_ids.id == table.id)
         return [query]
 
     @staticmethod
@@ -804,8 +779,7 @@ class Asset(SymbolMixin, ModelSQL, ModelView):
 
         query = tab_ids.select(
                 getattr(tab_ids, 'isin'),
-                where=tab_ids.id == table.id,
-            )
+                where=tab_ids.id == table.id)
         return [query]
 
     @staticmethod
@@ -818,8 +792,7 @@ class Asset(SymbolMixin, ModelSQL, ModelView):
 
         query = tab_ids.select(
                 getattr(tab_ids, 'secsymb'),
-                where=tab_ids.id == table.id,
-            )
+                where=tab_ids.id == table.id)
         return [query]
 
     @classmethod
@@ -839,8 +812,7 @@ class Asset(SymbolMixin, ModelSQL, ModelView):
             ).select(
                 tab_asset.id,
                 where=Operator(field_qu, clause[2]) &
-                (field_qu != DEF_NONE),
-            )
+                (field_qu != DEF_NONE))
 
         return [('id', 'in', query)]
 
@@ -913,7 +885,7 @@ class Asset(SymbolMixin, ModelSQL, ModelView):
             if OnlineSource.update_rate(asset):
                 to_run_activities.append(asset)
 
-        if len(to_run_activities) > 0:
+        if to_run_activities:
             cls.after_update_actions(to_run_activities)
 
 # end Asset
diff --git a/diagram.py b/diagram.py
index 08c7cab..1d654e9 100644
--- a/diagram.py
+++ b/diagram.py
@@ -95,7 +95,7 @@ class ChartPoint(metaclass=PoolMeta):
         """
         Rate = Pool().get('investment.rate')
 
-        if keyname is None:
+        if not keyname:
             return None
 
         # check if query is for us
diff --git a/import_wiz.py b/import_wiz.py
index 4722557..5a4d097 100644
--- a/import_wiz.py
+++ b/import_wiz.py
@@ -84,14 +84,14 @@ class ImportWizard(Wizard):
         pool = Pool()
         ImportWiz = pool.get('investment.imp_wiz', type='wizard')
 
-        if self.start.file_ is not None:
+        if self.start.file_:
             (lines, max_date, min_date) = ImportWiz.read_csv_file(
-                    self.start.file_.decode('utf8'),
-                    dec_divider=self.start.dec_divider,
-                    date_fmt=self.start.date_fmt,
-                    delimiter=self.start.field_delimiter)
+                self.start.file_.decode('utf8'),
+                dec_divider=self.start.dec_divider,
+                date_fmt=self.start.date_fmt,
+                delimiter=self.start.field_delimiter)
 
-            if len(lines) > 0:
+            if lines:
                 ImportWiz.upload_rates(
                     self.start.asset,
                     lines, min_date, max_date)
diff --git a/onlinesource.py b/onlinesource.py
index 4ebad01..abda8b4 100644
--- a/onlinesource.py
+++ b/onlinesource.py
@@ -63,16 +63,14 @@ class OnlineSource(ModelSQL, ModelView):
     url = fields.Char(string='URL', states=STATES_WEB, depends=DEPENDS_WEB)
     fixed_url = fields.Boolean(
         string='Fixed URL',
-        states={
-            'invisible': Eval('query_method', '') != 'web',
-        }, depends=DEPENDS_WEB,
+        states={'invisible': Eval('query_method', '') != 'web'},
+        depends=DEPENDS_WEB,
         help='URL must be defined at investment record.')
     nohtml = fields.Boolean(
         string='Remove HTML',
         help='Removes HTML tags before the text is interpreted.',
-        states={
-            'invisible': STATES_WEB['invisible'],
-        }, depends=DEPENDS_WEB)
+        states={'invisible': STATES_WEB['invisible']},
+        depends=DEPENDS_WEB)
     rgxdate = fields.Char(
         string='Date',
         help='Regex code to find the date in the downloaded HTML file.',
@@ -92,9 +90,8 @@ class OnlineSource(ModelSQL, ModelView):
     rgxident = fields.Char(
         string='Identifier',
         help='Regex code to find the identifier in the downloaded HTML file.',
-        states={
-            'invisible': STATES_WEB['invisible'],
-        }, depends=DEPENDS_WEB)
+        states={'invisible': STATES_WEB['invisible']},
+        depends=DEPENDS_WEB)
     rgxidtype = fields.Selection(
         string='ID-Type', selection=sel_rgxidtype,
         help='Type of identifier used to validate the result.',
@@ -243,16 +240,13 @@ class OnlineSource(ModelSQL, ModelView):
                 isin=self.isin,
                 nsin=self.nsin,
                 symbol=self.symbol,
-                url=self.url,
-                )
+                url=self.url)
 
     @classmethod
     def get_query_methods(cls):
         """ get list of query-methods
         """
-        return [
-            ('web', gettext('investment.msg_querytype_web')),
-            ]
+        return [('web', gettext('investment.msg_querytype_web'))]
 
     @classmethod
     def set_test_value(cls, record, name, value):
@@ -289,8 +283,7 @@ class OnlineSource(ModelSQL, ModelView):
                 nsin=nsin,
                 symbol=symbol,
                 debug=debug,
-                url=url,
-                )
+                url=url)
 
     def call_online_source(self):
         """ use updated values to call online-source,
@@ -301,7 +294,7 @@ class OnlineSource(ModelSQL, ModelView):
         result = OSourc.run_query_method(
             self, self.isin, self.nsin, self.url,
             self.symbol, debug=True)
-        if result is not None:
+        if result:
             self.text = result.get('text', None)
             self.http_state = result.get('http_state', None)
             self.fnddate = result.get('date', None)
@@ -342,8 +335,7 @@ class OnlineSource(ModelSQL, ModelView):
                     isin=asset.isin,
                     nsin=asset.wkn,
                     symbol=asset.secsymb,
-                    url=asset.updturl,
-                    )
+                    url=asset.updturl)
 
             if len(updtsource.rgxident or '') > 0:
                 # check result - same code?
@@ -360,15 +352,13 @@ class OnlineSource(ModelSQL, ModelView):
                             'update_rate: got wrong code ' +
                             '"%(wrong)s" - expected "%(exp)s"' % {
                                 'exp': asset_code,
-                                'wrong': code,
-                                })
+                                'wrong': code})
                         continue
 
             to_create = {
                 'date': rate_data.get('date', None),
                 'rate': rate_data.get('rate', None),
-                'asset': asset.id,
-                }
+                'asset': asset.id}
             if (to_create['date'] is not None) and \
                     (to_create['rate'] is not None):
                 # check if exists
@@ -443,8 +433,7 @@ class OnlineSource(ModelSQL, ModelView):
                 isin=isin,
                 nsin=nsin,
                 symbol=symbol,
-                url=url,
-                ),
+                url=url),
             allow_redirects=True,
             timeout=5.0)
 
diff --git a/update_wiz.py b/update_wiz.py
index 64f9359..50a36a3 100644
--- a/update_wiz.py
+++ b/update_wiz.py
@@ -29,7 +29,7 @@ class UpdateSoureWizard(Wizard):
             if OnlineSource.update_rate(asset):
                 to_run_activities.append(asset)
 
-        if len(to_run_activities) > 0:
+        if to_run_activities:
             Asset.after_update_actions(to_run_activities)
 
         return 'end'