code: def _is_leap_year(year):
      
      isleap = ((np.mod(year, 4) == 0) &
                ((np.mod(year, 100) != 0) | (np.mod(year, 400) == 0)))
      return isleap
docs: Determine if a year is leap year.
  
      Parameters
      ----------
      year : numeric
  
      Returns
      -------
      isleap : array of bools