code: public static String[] getDataTypesId()
      {
          Set<String> dataTypeIds = new HashSet<String>();
          for(Datatype datatype : miriam.getDatatype()) {
          	dataTypeIds.add(datatype.getId());
          }
          return dataTypeIds.toArray(new String[] {});
      }
docs: Retrieves the internal identifier (stable and perennial) of
  all the data types (for example: "MIR:00000005").
  
  @return list of the identifier of all the data types