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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_converter(self, converter_str):
 """find converter function reference by name find converter by name, converter name follows this convention: Class.method or: method The first type of converter class/function must be available in current module. The second type of converter must be available in `__builtin__` (or `builtins` in python3) module. :param converter_str: string representation of the converter func :return: function reference """

        ret = None
        if converter_str is not None:
            converter_desc_list = converter_str.split('.')
            if len(converter_desc_list) == 1:
                converter = converter_desc_list[0]
                # default to `converter`
                ret = getattr(cvt, converter, None)

                if ret is None:
                    # try module converter
                    ret = self.get_converter(converter)

                if ret is None:
                    ret = self.get_resource_clz_by_name(converter)

                if ret is None:
                    ret = self.get_enum_by_name(converter)

                if ret is None:
                    # try parser config
                    ret = self.get(converter)

            if ret is None and converter_str is not None:
                raise ValueError(
                    'Specified converter not supported: {}'.format(
                        converter_str))
        return ret