Removes the edge ``u_vertex -> v_vertex`` from the graph if the edge is present.

        :param u_vertex: Vertex
        :param v_vertex: Vertex
        :return: ``True`` if the existing edge was removed. ``False`` otherwise.

def del_edge(self, u_vertex, v_vertex):
        """Removes the edge ``u_vertex -> v_vertex`` from the graph if the edge is present.

        :param u_vertex: Vertex
        :param v_vertex: Vertex
        :return: ``True`` if the existing edge was removed. ``False`` otherwise.
        """
        if self.is_edge(u_vertex, v_vertex):
            self.indegrees[v_vertex] -= 1
            self.adj_dict[u_vertex].remove(v_vertex)
            return True

        return False