code: def fanpower_bhp(ddtt):
      
      from eppy.bunch_subclass import BadEPFieldError # here to prevent circular dependency
      try:
          fan_tot_eff = ddtt.Fan_Total_Efficiency # from V+ V8.7.0 onwards
      except BadEPFieldError as e:
          fan_tot_eff = ddtt.Fan_Efficiency 
      pascal = float(ddtt.Pressure_Rise)
      if str(ddtt.Maximum_Flow_Rate).lower() == 'autosize': 
      # str can fail with unicode chars :-(
          return 'autosize'
      else:
          m3s = float(ddtt.Maximum_Flow_Rate)
      return fan_bhp(fan_tot_eff, pascal, m3s)
docs: return fan power in bhp given the fan IDF object