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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def state_transition_is_valid( nameop ):
 """ Is this a valid state transition? """

    assert '__state_transition__' in nameop, "Not tagged with @state_transition"
    assert nameop['__state_transition__'], "BUG: @state_transition tagged False"
    assert '__history_id_key__' in nameop, "Missing __history_id_key__"
    history_id_key = nameop['__history_id_key__']
    assert history_id_key in ["name", "namespace_id"], "Invalid history ID key '%s'" % history_id_key
    assert '__table__' in nameop, "Missing __table__"
    assert '__always_set__' in nameop, "No always-set fields given"
    assert '__account_payment_info__' in nameop, 'No account payment information present'

    return True