Support Python 2.7 idioms #361

Do not mix return and generators in functions for Py2

Signed-off-by: Philippe Ombredanne <pombredanne@nexb.com>

Author: pombredanne

src/attributecode/transform.py

@@ -94,7 +94,8 @@ def transform_data(rows, transformer):
     if errors:
         return column_names, data, errors
 
-    data = transformer.filter_rows(data)
+    if transformer.row_filters:
+        data = list(transformer.filter_rows(data))
 
     return column_names, data, errors
 
@@ -253,12 +254,7 @@ def filter_columns(self, data):
         columns with a name in the `column_filters`of this Transformer.
         Return the data unchanged if no `column_filters` exists.
         """
-        column_filters = self.column_filters
-        if not column_filters:
-            return data
-
-        column_filters = set(self.clean_columns(column_filters))
-
+        column_filters = set(self.clean_columns(self.column_filters))
         for entry in data:
             items = ((k, v) for k, v in entry.items() if k in column_filters)
             yield OrderedDict(items)
@@ -271,9 +267,6 @@ def filter_rows(self, data):
         Transformer.
         """
         filters = self.row_filters
-        if not filters:
-            return data
-
         for entry in data:
             for filt in filters:
                 for filtered_column_name, filtered_column_value in filt.items():