convert characters (like '10:05 am') into python datetime format, despite likely formatting errors; list of errors / formats is extensible

fix_time.py

# Import times with a variety of broken formatting
# g_time_string is a character string
# g_time is the datetime object to produce

if g_time_string[-1] == 'n':
    g_time_string = g_time_string[0:-1] + "m"
g_time = None

# Various formatting for time, including common mistakes
time_formats = ["%I:%M %p", "%I:%M%p", "%I::%M %p", "%I;%M %p", "%I: %M %p", "%I:%M", "%I;%M%p",
                "%I:%M p%p", "%I:%M0%p"]
for tf in time_formats:
    # The try / except captures the error so we can attempt the next format
    try:
        g_time = datetime.datetime.strptime(g_time_string, tf)
        break
    except ValueError:
        continue

# If we couldn't match any formatting, re-raise the error
if g_time is None:
    raise ValueError('Could not match time format for %s' %g_time_string)