

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





def  _snake_case		(snake_case_					:     list  )							->		float:
  if not isinstance(snake_case_    ,       snake_case_  ):
    raise ValueError('Input series is not valid, valid series - [2, 4, 6]'  )
  if len(snake_case_  ) == 0:
    raise ValueError('Input list must be a non empty list'  )
  __UpperCAmelCase	:  Optional[int]		=     0
  for val in series:
    answer += 1 / val
  return len(snake_case_  ) / answer


if __name__ == "__main__":
      import doctest

      doctest.testmod()












'''simple docstring'''

from __future__ import annotations




def  _a     (				lowerCAmelCase_						):





      """simple docstring"""



      _snake_case		:						List[str]         =  sorted(lowerCAmelCase_						)
      _snake_case		:						Any         =  len(lowerCAmelCase_						)
      _snake_case		:						List[str]         =  length >> 1
      return (
          (sorted_list[mid_index] + sorted_list[mid_index - 1]) / 2
          if length % 2 == 0
          else sorted_list[mid_index]
      )




def  _a     (				):





      """simple docstring"""



      import doctest

      doctest.testmod()


if __name__ == "__main__":
   main()


