code: def ccor(alt, r, h1, zh):
      
      e = (alt - zh) / h1
      if(e>70.0):
          return 1.0 # exp(0) # pragma: no cover
      elif (e < -70.0):
          return exp(r)
      ex = exp(e)
      e = r / (1.0 + ex)
      return exp(e)
docs: /*        CHEMISTRY/DISSOCIATION CORRECTION FOR MSIS MODELS
   *         ALT - altitude
   *         R - target ratio
   *         H1 - transition scale length
   *         ZH - altitude of 1/2 R
   */