
'''simple docstring'''



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





def  _A		(							lowercase__	):
						if not isinstance(lowercase__		,		lowercase__	):
												raise ValueError("""Input series is not valid, valid series - [2, 4, 6]"""	)
						if len(lowercase__	) == 0:
												raise ValueError("""Input list must be a non empty list"""	)
						lowercase__							 =       0
						for val in series:
												answer += 1 / val
						return len(lowercase__	) / answer


if __name__ == "__main__":
				import doctest

				doctest.testmod()








'''simple docstring'''



def  _A		(							lowercase__	):

						# validate:
						if not isinstance(lowercase__		,		lowercase__	) or not all(
						    isinstance(lowercase__		,		lowercase__	) and item >= 0 for item in citations	):
												raise ValueError("""The citations should be a list of non negative integers."""	)

						citations.sort()
						lowercase__							 =       len(lowercase__	)

						for i in range(lowercase__	):
												if citations[len_citations - 1 - i] <= i:
																		return i

						return len_citations


if __name__ == "__main__":
				import doctest

				doctest.testmod()






