init init_abraassignmethid (
		n_obra: nullable TObra,
		n_cbra: nullable TCbra,
		n_assign: nullable TAssign
	)
	do
		_n_obra = n_obra.as(not null)
		n_obra.parent = self
		_n_cbra = n_cbra.as(not null)
		n_cbra.parent = self
		_n_assign = n_assign.as(not null)
		n_assign.parent = self
	end