docs: def build(self, builder):
          """Build XML by appending to builder"""
  
          params = dict(OID=self.oid, Name=self.name)
          if self.field_number is not None:
              params["FieldNumber"] = str(self.field_number)
  
          builder.start("mdsol:LabelDef", params)
  
          for translation in self.translations:
              translation.build(builder)
  
          for view_restriction in self.view_restrictions:
              view_restriction.build(builder)
  
          builder.end("mdsol:LabelDef")