code: def update_from(self, source, incr=1, force=False):
          
  
          # Make sure source is a parent or peer
          if source is self.parent or getattr(source, 'parent', None) is self.parent:
  
              if self.count + incr < 0 or source.count - incr < 0:
                  raise ValueError('Invalid increment: %s' % incr)
  
              if source is self.parent:
                  if self.parent.count - self.parent.subcount - incr < 0:
                      raise ValueError('Invalid increment: %s' % incr)
  
              else:
                  source.count -= incr
  
              self.count += incr
              self.parent.update(0, force)
  
          else:
              raise ValueError('source must be parent or peer')
docs: Args:
              source(:py:class:`SubCounter`): :py:class:`SubCounter` or :py:class:`Counter`
                  to increment from
              incr(int): Amount to increment ``count`` (Default: 1)
              force(bool): Force refresh even if ``min_delta`` has not been reached
  
          Move a value to this counter from another counter.
  
          ``source`` must be the parent :py:class:`Counter` instance or a :py:class:`SubCounter` with
          the same parent