code: def rfc2426(self):
          
          if self.uri:
              return rfc2425encode(self.name,self.uri,{"value":"uri"})
          elif self.image:
              if self.type:
                  p={"type":self.type}
              else:
                  p={}
              return rfc2425encode(self.name,self.image,p)
docs: RFC2426-encode the field content.
  
          :return: the field in the RFC 2426 format.
          :returntype: `str`