def _generator_transfer(m, t):
  """
    Constraint rule for electricity generation in generator
    @ In, m, pyo.ConcreteModel, model containing problem
    @ In, t, int, time indexer
    @ Out, constraint, bool, constraining evaluation
  """
  return - m.elec_generator_production[0, t] == 2.0 * m.elec_generator_production[1, t]