def       a__      (					a							)		->	List[str]:
       if not isinstance(__UpperCamelCase  ,   __UpperCamelCase							):
              raise ValueError('''Input series is not valid, valid series - [1, 2/3, 2]'''							)
       if len(__UpperCamelCase							) == 0:
              raise ValueError('''Input list must be a non empty list'''							)
       if len(__UpperCamelCase							) == 1 and series[0] != 0:
              return True
       A_							:       str	      =				[]
       A_							:       str	      =				len(__UpperCamelCase							)
       for i in range(0  ,   __UpperCamelCase							):
              if series[i] == 0:
                     raise ValueError('''Input series cannot have 0 as an element'''							)
              rec_series.append(1 / series[i]							)
       A_							:       int	      =				rec_series[1] - rec_series[0]
       for index in range(2  ,   __UpperCamelCase							):
              if rec_series[index] - rec_series[index - 1] != common_diff:
                     return False
       return True


def       a__      (					a							)		->	Tuple:
       if not isinstance(__UpperCamelCase  ,   __UpperCamelCase							):
              raise ValueError('''Input series is not valid, valid series - [2, 4, 6]'''							)
       if len(__UpperCamelCase							) == 0:
              raise ValueError('''Input list must be a non empty list'''							)
       A_							:       List[Any]	      =				0
       for val in series:
              answer += 1 / val
       return len(__UpperCamelCase							) / answer


if __name__ == "__main__":
    import doctest

    doctest.testmod()





"""simple docstring"""






from typing import Callable
def 		A_	(   __UpperCamelCase     :				Callable				):

		def wrapper(__UpperCamelCase     :				Optional[Any]				):
				lowercase										=							function_with_docstring.__doc__
				return target_function

		return wrapper