fix style issues

src/pysqllike/generic/column_group_operator.py

@@ -4,8 +4,6 @@
 @brief Creates custom classes to interpret Python expression as column operations.
 """
 
-import collections
-
 from .column_operator import ColumnOperator
 from .others_types import NA
 
@@ -52,9 +50,6 @@ def __call__(self, columns):
         """
         returns the results of this operation between a list of columns
         """
-        if not isinstance(columns, collections.Iterable):
-            raise TypeError(
-                "we expect an iterator here not " + str(type(columns)))
         return len(columns)
 
 
@@ -75,10 +70,6 @@ def __call__(self, columns):
         returns the results of this operation between a list of columns,
         it returns @see cl NA for a null set
         """
-        if not isinstance(columns, collections.Iterable):
-            raise TypeError(
-                "we expect an iterator here not " + str(type(columns)))
-
         # we walk through the set only once
         nb = 0
         for val in columns:

src/pysqllike/generic/column_type.py

@@ -4,7 +4,6 @@
 @brief Classes which defines column for class @see cl IterRow
 """
 from inspect import isfunction
-import collections
 from .iter_exceptions import IterException, NotAllowedOperation
 from .others_types import long, NA, EmptyGroup, GroupByContainer
 
@@ -727,8 +726,7 @@ def set(self, value):
         @param      value       anything in [int,float,long,str, function ]
         """
         self._value = value
-        if isinstance(value, collections.Iterable) and \
-                not isinstance(value, str) and \
+        if not isinstance(value, str) and \
                 not isinstance(value, GroupByContainer):
             raise IterException(
                 "type of value should be GroupByContainer not {0} for the column {1}".format(