code: def rational_limit(f, g, t0):
      
      assert isinstance(f, np.poly1d) and isinstance(g, np.poly1d)
      assert g != np.poly1d([0])
      if g(t0) != 0:
          return f(t0)/g(t0)
      elif f(t0) == 0:
          return rational_limit(f.deriv(), g.deriv(), t0)
      else:
          raise ValueError("Limit does not exist.")
docs: Computes the limit of the rational function (f/g)(t)
      as t approaches t0.