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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 resolve_pname(self, pname: PrefName, mid: ModuleId) -> Tuple[YangIdentifier, ModuleId]: """Return the name and module identifier in which the name is defined. Args: pname: Name with an optional prefix. mid: Identifier of the module in which `pname` appears. Raises: ModuleNotRegistered: If `mid` is not registered in the data model. UnknownPrefix: If the prefix specified in `pname` is not declared. """

        p, s, loc = pname.partition(":")
        try:
            mdata = self.modules[mid]
        except KeyError:
            raise ModuleNotRegistered(*mid) from None
        try:
            return (loc, mdata.prefix_map[p]) if s else (p, mdata.main_module)
        except KeyError:
            raise UnknownPrefix(p, mid) from None