message: guard against atom_site not being available
diff: @@ -29,7 +29,7 @@ namespace BestDatabaseSequenceMapping {
  type: 'static',
  defaultParams: {},
  getParams: () => ({}),
  - isApplicable: (data: Model) => MmcifFormat.is(data.sourceData) && data.sourceData.data.frame.categories?.atom_site.fieldNames.indexOf('db_name') >= 0,
  + isApplicable: (data: Model) => MmcifFormat.is(data.sourceData) && data.sourceData.data.frame.categories?.atom_site?.fieldNames.indexOf('db_name') >= 0,
  obtain: async (ctx, data) => {
  return { value: fromCif(data) };
  }
  