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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 _is_call2custom_manager(node):
 """Checks if the call is being done to a custom queryset manager."""

    called = safe_infer(node.func)
    funcdef = getattr(called, '_proxied', None)
    return _is_custom_qs_manager(funcdef)