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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 _get_member_ref_str(name, obj, role='obj', known_refs=None):
 """generate a ReST-formmated reference link to the given `obj` of type `role`, using `name` as the link text"""

    if known_refs is not None:
        if name in known_refs:
            return known_refs[name]
    ref = _get_fullname(name, obj)
    return ":%s:`%s <%s>`" % (role, name, ref)