code: def is_smooth_from(self, previous, warning_on=True):
          
          if warning_on:
              warn(_is_smooth_from_warning)
          if isinstance(previous, QuadraticBezier):
              return (self.start == previous.end and
                      (self.control - self.start) == (
                          previous.end - previous.control))
          else:
              return self.control == self.start
docs: [Warning: The name of this method is somewhat misleading (yet kept
          for compatibility with scripts created using svg.path 2.0).  This
          method is meant only for d string creation and should not be used to
          check for kinks.  To check a segment for differentiability, use the
          joins_smoothly_with() method instead.]