code: def utc_strftime(self, format):
          
          tup = self._utc_tuple(_half_second)
          year, month, day, hour, minute, second = tup
          second = second.astype(int)
          zero = zeros_like(year)
          tup = (year, month, day, hour, minute, second, zero, zero, zero)
          if self.shape:
              return [strftime(format, item) for item in zip(*tup)]
          else:
              return strftime(format, tup)
docs: Format the UTC time using a Python date formatting string.
  
          This internally calls the Python ``strftime()`` routine from the
          Standard Library ``time()`` module, for which you can find a
          quick reference at ``http://strftime.org/``.  If this object is
          an array of times, then a sequence of strings is returned
          instead of a single string.