code: def squish(incs, f):
      
      incs = np.radians(incs)
      I_o = f * np.tan(incs)  # multiply tangent by flattening factor
      return np.degrees(np.arctan(I_o))
docs: returns 'flattened' inclination, assuming factor, f and King (1955) formula:
      tan (I_o) = f tan (I_f)
  
      Parameters
      __________
      incs : array of inclination (I_f)  data to flatten
      f : flattening factor
  
      Returns
      _______
      I_o :  inclinations after flattening