def __sub__ ( self , other ) : return self . __class__ ( [ elem for elem in self if elem not in other ] )
python items in alist that are not in the other
Return a Cache containing the entries of self that are not in other .
def __sub__(self, other):
		"""
		Return a Cache containing the entries of self that are not in other.
		"""
		return self.__class__([elem for elem in self if elem not in other])