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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def expand_families(self, stmts):
 """Generate statements by expanding members of families and complexes. """

        new_stmts = []
        for stmt in stmts:
            # Put together the lists of families, with their members. E.g.,
            # for a statement involving RAF and MEK, should return a list of
            # tuples like [(BRAF, RAF1, ARAF), (MAP2K1, MAP2K2)]
            families_list = []
            for ag in stmt.agent_list():
                ag_children = self.get_children(ag)
                # If the agent has no children, then we use the agent itself
                if len(ag_children) == 0:
                    families_list.append([ag])
                # Otherwise, we add the tuple of namespaces/IDs for the children
                else:
                    families_list.append(ag_children)
            # Now, put together new statements frmo the cross product of the
            # expanded family members
            for ag_combo in itertools.product(*families_list):
                # Create new agents based on the namespaces/IDs, with
                # appropriate name and db_refs entries
                child_agents = []
                for ag_entry in ag_combo:
                    # If we got an agent, or None, that means there were no
                    # children; so we use the original agent rather than
                    # construct a new agent
                    if ag_entry is None or isinstance(ag_entry, Agent):
                        new_agent = ag_entry
                    # Otherwise, create a new agent from the ns/ID
                    elif isinstance(ag_entry, tuple):
                        # FIXME FIXME FIXME
                        # This doesn't reproduce agent state from the original
                        # family-level statements!
                        ag_ns, ag_id = ag_entry
                        new_agent = _agent_from_ns_id(ag_ns, ag_id)
                    else:
                        raise Exception('Unrecognized agent entry type.')
                    # Add agent to our list of child agents
                    child_agents.append(new_agent)
                # Create a copy of the statement
                new_stmt = deepcopy(stmt)
                # Replace the agents in the statement with the newly-created
                # child agents
                new_stmt.set_agent_list(child_agents)
                # Add to list
                new_stmts.append(new_stmt)
        return new_stmts