Registers a callback for log handling. The callback is invoked
    with given arguments: `logger`, `level`, `msg`, `args` and `kwargs`
    which are the values passed to the logging system. If the callback
    returns true value the default handling is disabled. Only one callback
    can be registered per one logger name. Logger tree is not traversed
    so calling this method with `spammy_module` argument will not silence
    messages from `spammy_module.child`.

def register_special_log_handler(name_or_logger, callback):
    """Registers a callback for log handling. The callback is invoked
    with given arguments: `logger`, `level`, `msg`, `args` and `kwargs`
    which are the values passed to the logging system. If the callback
    returns true value the default handling is disabled. Only one callback
    can be registered per one logger name. Logger tree is not traversed
    so calling this method with `spammy_module` argument will not silence
    messages from `spammy_module.child`.
    """
    if isinstance(name_or_logger, string_types):
        name = name_or_logger
    else:
        name = name_or_logger.name
    special_logger_handlers[name] = callback