code: def add_group(self, group_attribs=None, parent=None):
          
          if parent is None:
              parent = self.tree.getroot()
          elif not self.contains_group(parent):
              warnings.warn('The requested group {0} does not belong to '
                            'this Document'.format(parent))
  
          if group_attribs is None:
              group_attribs = {}
          else:
              group_attribs = group_attribs.copy()
  
          return SubElement(parent, '{{{0}}}g'.format(
              SVG_NAMESPACE['svg']), group_attribs)
docs: Add an empty group element to the SVG.