code: def length(self, t0=0, t1=1, error=LENGTH_ERROR, min_depth=LENGTH_MIN_DEPTH):
          
          assert 0 <= t0 <= 1 and 0 <= t1 <= 1
          if _quad_available:
              return quad(lambda tau: abs(self.derivative(tau)), t0, t1,
                          epsabs=error, limit=1000)[0]
          else:
              return segment_length(self, t0, t1, self.point(t0), self.point(t1),
                                    error, min_depth, 0)
docs: The length of an elliptical large_arc segment requires numerical
          integration, and in that case it's simpler to just do a geometric
          approximation, as for cubic bezier curves.