def METHOD_NAME(cmd):
    """Run a command and return its stdout/stderr as a string.
    Parameters
    ----------
    cmd : str or list
        A command to be executed in the system shell.
    Returns
    -------
    output : str
        A string containing the combination of stdout and stderr from the
    subprocess, in whatever order the subprocess originally wrote to its
    file descriptors (so the order of the information in this string is the
    correct order as would be seen if running the command in a terminal).
    """
    out = process_handler(cmd, lambda p: p.communicate()[0], subprocess.STDOUT)
    if out is None:
        return ''
    return py3compat.decode(out)