code: public void addIntermediateSchema(Schema schema) throws TupleMRException {
      if (schemaAlreadyExists(schema.getName())) {
        throw new TupleMRException("There's a schema with that name '" + schema.getName()
            + "'");
      }
      schemas.add(schema);
    }
docs: Adds a Map-output schema. Tuples emitted by TupleMapper will use one of the
  schemas added by this method. Schemas added in consecutive calls to this
  method must be named differently.