code: def log(x, base=None):
      
      if base == 10:
          return np.log10(x)
      elif base == 2:
          return np.log2(x)
      elif base is None or base == np.e:
          return np.log(x)
      else:
          return np.log(x)/np.log(base)
docs: Calculate the log
  
      Parameters
      ----------
      x : float or array_like
          Input values
      base : int or float (Default: None)
          Base of the log. If `None`, the natural logarithm
          is computed (`base=np.e`).
  
      Returns
      -------
      out : float or ndarray
          Calculated result