In reply to mukul1996:
m_sequencer is a member of a sequence. You can’t call a.start(m_sequencer) unless you are already in a sequence. It’s the default if you don’t specify a sequencer.
Normally the agent will start the sequence in its run_phase, and it has a handle to the sequencer. Or the test can start each sequence and will need to get a handle to each sequencer. There are a variety of other scenarios.