def _get_data_bytes_only(param_name, param_value):
if param_value is None:<EOL><INDENT>return b'<STR_LIT>'<EOL><DEDENT>if isinstance(param_value, bytes):<EOL><INDENT>return param_value<EOL><DEDENT>raise TypeError(_ERROR_VALUE_SHOULD_BE_BYTES.format(param_name))<EOL>
Validates the request body passed in and converts it to bytes
    if our policy allows it.