code: def annualization_factor(period, annualization):
      
      if annualization is None:
          try:
              factor = ANNUALIZATION_FACTORS[period]
          except KeyError:
              raise ValueError(
                  "Period cannot be '{}'. "
                  "Can be '{}'.".format(
                      period, "', '".join(ANNUALIZATION_FACTORS.keys())
                  )
              )
      else:
          factor = annualization
      return factor
docs: Return annualization factor from period entered or if a custom
      value is passed in.
  
      Parameters
      ----------
      period : str, optional
          Defines the periodicity of the 'returns' data for purposes of
          annualizing. Value ignored if `annualization` parameter is specified.
          Defaults are::
  
              'monthly':12
              'weekly': 52
              'daily': 252
  
      annualization : int, optional
          Used to suppress default values available in `period` to convert
          returns into annual returns. Value should be the annual frequency of
          `returns`.
  
      Returns
      -------
      annualization_factor : float