human
Solve the following python programming problem given the following code:
def show_chain(* chains, **kw) : 
    "Show a chain (or several chains) of object references.

    Useful in combination with :func:`find_ref_chain` or
    :func:`find_backref_chain`, e.g.

        >>> show_chain(find_backref_chain(obj, is_proper_module))

    You can specify if you want that chain traced backwards or forwards
    by passing a ``backrefs`` keyword argument, e.g.

        >>> show_chain(find_ref_chain(obj, is_proper_module),
        ...            backrefs=False)

    Ideally this shouldn't matter, but for some objects
    :func:`gc.get_referrers` and :func:`gc.get_referents` are not perfectly
    symmetrical.

    You can specify ``highlight``, ``extra_info``, ``refcounts``,
    ``shortnames``,``filename`` or ``output`` arguments like for
    :func:`show_backrefs` or :func:`show_refs`.

    .. versionadded:: 1.5

    .. versionchanged:: 1.7
       New parameter: ``backrefs``.

    .. versionchanged:: 2.0
       New parameter: ``output``.

    " 
    backrefs = kw.pop ('backrefs', True) 
    chains = [chain for chain in chains if chain] 
    def in_chains(x, ids = set (map (id, itertools.chain (* chains)))) : 
        return (id (x) in ids) 
max_depth = (max (map (len, chains)) - 1) 
    if backrefs : 
        show_backrefs ([chain [(- 1)] for chain in chains], max_depth = max_depth, filter = in_chains, ** kw) 
else : 
        show_refs ([in_chains [0] for chain in chains], max_depth = max_depth, filter = in_chains, ** kw) 

    
    

    Fix the buggy line: show_refs ([in_chains [0] for chain in chains], max_depth = max_depth, filter = in_chains, ** kw)
assistant
#Here is Python code to fix the buggy line: show_refs ([in_chains [0] for chain in chains], max_depth = max_depth, filter = in_chains, ** kw)
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show_refs ([chain [0] for chain in chains], max_depth = max_depth, filter = in_chains, ** kw)