<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def _py_to_couch_translate(key, val):
 """ Performs the conversion of the Python parameter value to its CouchDB equivalent. """

    try:
        if key in ['keys', 'endkey_docid', 'startkey_docid', 'stale', 'update']:
            return {key: val}
        if val is None:
            return {key: None}
        arg_converter = TYPE_CONVERTERS.get(type(val))
        return {key: arg_converter(val)}
    except Exception as ex:
        raise CloudantArgumentError(136, key, ex)