def unix_timestamp_to_datetime(unix_timestamp):
<EOL>securesystemslib.formats.UNIX_TIMESTAMP_SCHEMA.check_match(unix_timestamp)<EOL>struct_time = time.gmtime(unix_timestamp)<EOL>datetime_object = datetime.datetime(*struct_time[:<NUM_LIT:6>])<EOL>return datetime_object<EOL>
<Purpose>
  Convert 'unix_timestamp' (i.e., POSIX time, in UNIX_TIMESTAMP_SCHEMA format)
  to a datetime.datetime() object.  'unix_timestamp' is the number of seconds
  since the epoch (January 1, 1970.)

  >>> datetime_object = unix_timestamp_to_datetime(1445455680)
  >>> datetime_object
  datetime.datetime(2015, 10, 21, 19, 28)

<Arguments>
  unix_timestamp:
    An integer representing the time (e.g., 1445455680).  Conformant to
    'securesystemslib.formats.UNIX_TIMESTAMP_SCHEMA'.

<Exceptions>
  securesystemslib.exceptions.FormatError, if 'unix_timestamp' is improperly
  formatted.

<Side Effects>
  None.

<Returns>
  A datetime.datetime() object corresponding to 'unix_timestamp'.