code: def Sh(L: float, h: float, D: float) -> float:
      
  
      return h * L / D
docs: Calculate the Sherwood number.
  
      :param L: [m] mass transfer surface characteristic length.
      :param h: [m/s] mass transfer coefficient.
      :param D: [m2/s] fluid mass diffusivity.
  
      :returns: float