def main():
"""."""
from vocabulary import Vocabulary
from attribute import Attribute
from attribute_structure import AttributeStructure
from attribute_system import AttributeSystem
vocabulary = Vocabulary(['C'], [], ['V'])
a = Attribute("a", [])
b = Attribute("b", [])
astr = AttributeStructure(a, b)
objs = ['a', 'b', 'c']
attribute_system = AttributeSystem(astr, objs)
C = ConstantAssignment(vocabulary, attribute_system, {'C': 'a'})
print C._vocabulary
vocabulary.add_constant("C2")
print C._vocabulary
