def _validate_dtype(self, dtype):
if dtype is not None:<EOL><INDENT>dtype = pandas_dtype(dtype)<EOL>if dtype.kind == '<STR_LIT>':<EOL><INDENT>raise NotImplementedError("<STR_LIT>"<EOL>"<STR_LIT>"<EOL>.format(self.__class__.__name__))<EOL><DEDENT><DEDENT>return dtype<EOL>
validate the passed dtype