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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_convert_method(self):
 """ Get right method to convert of the value. """

        for type_, method in self._map.items():
            if type(self.value) is bool and type_ is not bool:
                continue
            if isinstance(self.value, type_):
                return method
        if is_sql_instance(self.value):
            return self._raw
        return self._undefined