docs: def build(self, builder):
          """Build XML by appending to builder"""
          params = {}
          if self.study_oid:
              params.update(dict(StudyOID=self.study_oid))
          builder.start("AdminData", params)
          for user in self.users:
              user.build(builder)
          for location in self.locations:
              location.build(builder)
  
          builder.end("AdminData")