def mechanismHub_dynamic_fee_percent(params, substep, state_history, prev_state, policy_input):
    """
    This mechanism returns the revenue generated from a dynamic fee.
    """
    asset = policy_input['asset_id']
    dynamic_rev = prev_state['dynamic_revenue']
    dynamic_rev[asset] = dynamic_rev[asset]+ policy_input['dynamic_fee']

    return 'dynamic_revenue', dynamic_rev