':param file_path: the path to the file that\'s being processed
:type file_path: unicode
:return: the current runtime (in seconds) of the process that\'s
processing the specified file or None if the file is not currently
being processed'

def get_runtime(self, file_path):

    if (file_path in self._processors):
        return (datetime.now() - self._processors[file_path].start_time).total_seconds()
    return None
