code: def _verify_pair(prev, curr):
          
          if prev._dimension != 2:
              raise ValueError("Curve not in R^2", prev)
  
          end = prev._nodes[:, -1]
          start = curr._nodes[:, 0]
          if not _helpers.vector_close(end, start):
              raise ValueError(
                  "Not sufficiently close",
                  "Consecutive sides do not have common endpoint",
                  prev,
                  curr,
              )
docs: Verify a pair of sides share an endpoint.
  
          .. note::
  
             This currently checks that edge endpoints match **exactly**
             but allowing some roundoff may be desired.
  
          Args:
              prev (.Curve): "Previous" curve at piecewise junction.
              curr (.Curve): "Next" curve at piecewise junction.
  
          Raises:
              ValueError: If the previous side is not in 2D.
              ValueError: If consecutive sides don't share an endpoint.