def ensure_operators_are_strings(value, criteria_pattern):
    """
    This function ensures that both value and criteria_pattern arguments are unicode (string)
    values if the input value type is bytes.

    If a value is of types bytes and not a unicode, it's converted to unicode. This way we
    ensure all the operators which expect string / unicode values work, even if one of the
    values is bytes (this can happen when input is not controlled by the end user - e.g. trigger
    payload under Python 3 deployments).

    :return: tuple(value, criteria_pattern)
    """
    if isinstance(value, bytes):
        value = value.decode("utf-8")

    if isinstance(criteria_pattern, bytes):
        criteria_pattern = criteria_pattern.decode("utf-8")

    return value, criteria_pattern

    This function ensures that both value and criteria_pattern arguments are unicode (string)
    values if the input value type is bytes.

    If a value is of types bytes and not a unicode, it's converted to unicode. This way we
    ensure all the operators which expect string / unicode values work, even if one of the
    values is bytes (this can happen when input is not controlled by the end user - e.g. trigger
    payload under Python 3 deployments).

    :return: tuple(value, criteria_pattern)
    
st2common/st2common/operators.py