Check if a list exists in given list of lists

[Daniel94]

I want to check if a list of tuples contains a specific tuple. If

numbers = [('a','a'), ('c','a')]
look = ('a','c')

"look" should not be contained in "numbers". But that's how my code thinks right now.

  def find_edge(self, src, dst):
        """
        Returns True if there's an edge from node `src` to node `dst`.
        """
        # Check if nodes exist
        if self.find_node(src) is True and self.find_node(dst) is True:
            src_node = self.return_head(src)

            src_edges = src_node.list_edges()
            src_edges_weightless = [x[:-1] for x in src_edges]

            possible_edge = (src, dst)

            for elem in src_edges_weightless:
                if collections.Counter(elem) == collections.Counter(possible_edge):
                    return True

        return False

So when looking if ("a","c") is contained in the list, return should be FALSE. However right now it returns TRUE. Any ideas why?