code: def insert_defs(self, defs):
          
          if self._svg["defs"] is None:
              self._svg["defs"] = {}
          for def_ in defs:
              for key, value in def_.items():
                  if key.startswith("@"):
                      continue
                  if key not in self._svg["defs"]:
                      self._svg["defs"][key] = []
                  if not isinstance(value, list):
                      value = [value]
                  self._svg["defs"][key].extend(value)
docs: Adds the defs to the SVG structure.
  
          :param defs: a list of SVG dictionaries, which contain the defs,
            which should be added to the SVG structure.