code: def re_pipe(FlowRate, Diam, Nu):
      
      #Checking input validity
      ut.check_range([FlowRate, ">0", "Flow rate"], [Diam, ">0", "Diameter"],
                     [Nu, ">0", "Nu"])
      return (4 * FlowRate) / (np.pi * Diam * Nu)
docs: Return the Reynolds Number for a pipe.