How to use the pyrfc.FunctionDescription function in pyrfc

def test_func_desc_manual(self):
        # Example taken from hardCodedServer (cf. Schmidt and Li, 2009c)
        animals = TypeDescription("animals", nuc_length=20, uc_length=28)
        self.assertEqual(animals.nuc_length,20)
        self.assertEqual(animals.uc_length,28)
        animals.add_field(name=u'LION', field_type='RFCTYPE_CHAR', nuc_length=5, uc_length=10, nuc_offset=0, uc_offset=0)
        animals.add_field(name=u'ELEPHANT', field_type='RFCTYPE_FLOAT', nuc_length=8, uc_length=8, decimals=16, nuc_offset=8, uc_offset=16)
        animals.add_field(name=u'ZEBRA', field_type='RFCTYPE_INT', nuc_length=4, uc_length=4, nuc_offset=16, uc_offset=24)

        i_dont_exist = FunctionDescription(u"I_DONT_EXIST")
        i_dont_exist.add_parameter(name=u"DOG", parameter_type="RFCTYPE_INT",
            direction="RFC_IMPORT", nuc_length=4, uc_length=4)
        i_dont_exist.add_parameter(name=u"CAT", parameter_type="RFCTYPE_CHAR",
            direction="RFC_IMPORT", nuc_length=5, uc_length=10)
        i_dont_exist.add_parameter(name=u"ZOO", parameter_type="RFCTYPE_STRUCTURE",
            direction="RFC_IMPORT", nuc_length=20, uc_length=28, type_description=animals)
        i_dont_exist.add_parameter(name=u"BIRD", parameter_type="RFCTYPE_FLOAT",
            direction="RFC_IMPORT", nuc_length=8, uc_length=8, decimals=16)

        self.assertEqual(len(i_dont_exist.parameters), 4)
        self.assertEqual(i_dont_exist.name, u"I_DONT_EXIST")

decimals=16,
    nuc_length=8,
    uc_length=8,
    nuc_offset=8,
    uc_offset=16,
)
animals.add_field(
    name=u"ZEBRA",
    field_type="RFCTYPE_INT",
    nuc_length=4,
    uc_length=4,
    nuc_offset=16,
    uc_offset=24,
)

func_desc = FunctionDescription("I_DONT_EXIST")
func_desc.add_parameter(
    name=u"DOC",
    field_type="RFCTYPE_INT",
    direction="RFC_IMPORT",
    nuc_length=4,
    uc_length=4,
)
func_desc.add_parameter(
    name=u"CAT",
    field_type="RFCTYPE_CHAR",
    direction="RFC_IMPORT",
    nuc_length=5,
    uc_length=10,
)
func_desc.add_parameter(
    name=u"ZOO",