UseTrait : UseNamespace Terminator
             | UseNamespace COLON Terminator UseTraitContent

def p_UseTrait(p):
    '''
    UseTrait : UseNamespace Terminator
             | UseNamespace COLON Terminator UseTraitContent
    '''
    if len(p) <= 3:
        p[0] = UseTrait(p[1], p[2], None)
    else:
        p[0] = UseTrait(p[1], p[3], p[4])