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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:
 async def AddPendingResources(self, application_tag, charm_url, resources):
 """Fix the calling signature of AddPendingResources. The ResourcesFacade doesn't conform to the standard facade pattern in the Juju source, which leads to the schemagened code not matching up properly with the actual calling convention in the API. There is work planned to fix this in Juju, but we have to work around it for now. application_tag : str charm_url : str resources : typing.Sequence<+T_co>[~CharmResource]<~CharmResource> Returns -> typing.Union[_ForwardRef('ErrorResult'), typing.Sequence<+T_co>[str]] """

        # map input types to rpc msg
        _params = dict()
        msg = dict(type='Resources',
                   request='AddPendingResources',
                   version=1,
                   params=_params)
        _params['tag'] = application_tag
        _params['url'] = charm_url
        _params['resources'] = resources
        reply = await self.rpc(msg)
        return reply