Put your network information in the prefix object.

def add_prefix(network):
    """ Put your network information in the prefix object. """
    p = new_prefix()
    p.prefix = str(network['network'])
    p.type = "assignment"
    p.description = network['description']
    p.tags = ['ipplan-import']
    p.comment = ""

    if 'additional' in network:
        p.comment += network['additional']
    if len(network['comment']) > 0:
        p.comment += network['comment']
    return p