def flag_time_err(phase_err, time_thresh=<NUM_LIT>):
time_err = []<EOL>for stamp in phase_err:<EOL><INDENT>if abs(stamp[<NUM_LIT:1>]) > time_thresh:<EOL><INDENT>time_err.append(stamp[<NUM_LIT:0>])<EOL><DEDENT><DEDENT>return time_err<EOL>
Find large time errors in list.

Scan through a list of tuples of time stamps and phase errors
and return a list of time stamps with timing errors above a threshold.

.. note::
    This becomes important for networks cross-correlations, where
    if timing information is uncertain at one site, the relative arrival
    time (lag) will be incorrect, which will degrade the cross-correlation
    sum.

:type phase_err: list
:param phase_err: List of Tuple of float, datetime.datetime
:type time_thresh: float
:param time_thresh: Threshold to declare a timing error for

:returns: List of :class:`datetime.datetime` when timing is questionable.