code: def irr(values, guess = None):
      
      if isinstance(values, Range):
          values = values.values
  
      if guess is not None and guess != 0:
          raise ValueError('guess value for excellib.irr() is %s and not 0' % guess)
      else:
          try:
              return np.irr(values)
          except Exception as e:
              return ExcelError('#NUM!', e)
docs: Function to calculate the internal rate of return (IRR) using payments and periodic dates. It resembles the
      excel function IRR().
  
      Excel reference: https://support.office.com/en-us/article/IRR-function-64925eaa-9988-495b-b290-3ad0c163c1bc
  
      :param values: the payments of which at least one has to be negative.
      :param guess: an initial guess which is required by Excel but isn't used by this function.
      :return: a float being the IRR.