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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_function(self, name: str) -> AbiFunction or None: """ This interface is used to get an AbiFunction object from AbiInfo object by given function name. :param name: the function name in abi file :return: if succeed, an AbiFunction will constructed based on given function name """

        for func in self.functions:
            if func['name'] == name:
                return AbiFunction(func['name'], func['parameters'], func.get('returntype', ''))
        return None