code: func licenseDefinition() (*design.LicenseDefinition, bool) {
  	l, ok := dslengine.CurrentDefinition().(*design.LicenseDefinition)
  	if !ok {
  		dslengine.IncompatibleDSL()
  	}
  	return l, ok
  }
docs: // licenseDefinition returns true and current context if it is an APIDefinition,
  // nil and false otherwise.