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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 export_kappa_im(model, fname=None):
 """Return a networkx graph representing the model's Kappa influence map. Parameters model : pysb.core.Model A PySB model to be exported into a Kappa IM. fname : Optional[str] A file name, typically with .png or .pdf extension in which the IM is rendered using pygraphviz. Returns ------- networkx.MultiDiGraph A graph object representing the influence map. """

    from .kappa_util import im_json_to_graph
    kappa = _prepare_kappa(model)
    imap = kappa.analyses_influence_map()
    im = im_json_to_graph(imap)
    for param in model.parameters:
        try:
            im.remove_node(param.name)
        except:
            pass
    if fname:
        agraph = networkx.nx_agraph.to_agraph(im)
        agraph.draw(fname, prog='dot')
    return im