code: def _xml(self, prefix=""):
      if self._unset:
          return ""
  
      s = 'style="'
      for key in _converters.keys():
          key_ = key.replace("-", "_")
          value = self.__getattribute__(key_)
          if value is not None:
              s += "%s:%s " % (key, value)
      s += '"'
      return s
  
file_path: vispy/vispy/util/svg/style.py
imports: from .color import Color
  from .number import Number
  from .length import Length
label_desc: Use image node_id 4 for calling the Style obj's underlying member method code with example usage: obj._xml(prefix) and returns: s, str