How to use the pelican.signals.initialized.connect function in pelican

def register():
    """Plugin registration"""
    signals.initialized.connect(pelican_init)
    # repeated
    signals.all_generators_finalized.connect(process_rst_and_summaries)

def register():
    """Plugin registration."""
    from pelican import signals

    signals.initialized.connect(setup_gist)

    signals.article_generator_finalized.connect(replace_gist_tags)

def register(): # for Pelican
    import pelican.signals

    pelican.signals.initialized.connect(_pelican_configure)

def register(): # for Pelican
    pelican.signals.initialized.connect(_pelican_configure)
    pelican.signals.readers_init.connect(_pelican_add_reader)

def register():
    signals.initialized.connect(pelican_initialized)
    signals.all_generators_finalized.connect(pelican_all_generators_finalized)