def METHOD_NAME():
    # +BEGINS_AT
    op.add_column(RHE, sa.Column(
        'begins_at', postgresql.TIMESTAMP(timezone=True),
        server_default=sa.text('CURRENT_TIMESTAMP'),
        autoincrement=False, nullable=False
    ))
    op.execute('update room_history_entry set begins_at = lower(active_during)')
    op.alter_column(RHE, 'begins_at', nullable=False)
    op.create_index('ix_room_history_entry_begins_at', RHE, ['begins_at'],
                    unique=False)
    ###
    # +ENDS_AT
    op.add_column(RHE,
                  sa.Column('ends_at', postgresql.TIMESTAMP(timezone=True), autoincrement=False,
                            nullable=True))
    op.execute('update room_history_entry set ends_at = upper(active_during)')
    op.create_index('ix_room_history_entry_ends_at', RHE, ['ends_at'],
                    unique=False)
    ###
    op.create_check_constraint(
        "room_history_entry_check", RHE,
        "ends_at is null or begins_at <= ends_at",
    )
    # +UNIQUENESS CHECK
    op.execute("""\