docs: def build(self, builder):
          """Build XML by appending to builder"""
          params = dict(
              OID=self.oid, Name=self.name, Repeating=bool_to_yes_no(self.repeating)
          )
  
          if self.order_number is not None:
              params["mdsol:OrderNumber"] = str(self.order_number)
  
          if self.active is not None:
              params["mdsol:Active"] = bool_to_yes_no(self.active)
  
          params["mdsol:Template"] = bool_to_yes_no(self.template)
          params["mdsol:SignatureRequired"] = bool_to_yes_no(self.signature_required)
          params["mdsol:LogDirection"] = self.log_direction
          params["mdsol:DoubleDataEntry"] = self.double_data_entry
          params["mdsol:ConfirmationStyle"] = self.confirmation_style
  
          if self.link_study_event_oid:
              params["mdsol:LinkStudyEventOID"] = self.link_study_event_oid
  
          if self.link_form_oid:
              params["mdsol:LinkFormOID"] = self.link_form_oid
  
          builder.start("FormDef", params)
          for itemgroup_ref in self.itemgroup_refs:
              itemgroup_ref.build(builder)
  
          for helptext in self.helptexts:
              helptext.build(builder)
  
          for view_restriction in self.view_restrictions:
              view_restriction.build(builder)
  
          for entry_restriction in self.entry_restrictions:
              entry_restriction.build(builder)
  
          for alias in self.aliases:
              alias.build(builder)
  
          builder.end("FormDef")