try:
    #it's ast in Python 2.6
    import ast
except ImportError:
    #it's _ast in Python 2.5
    import _ast as ast

def astnode_genAssign( targets, value):
    tmp = ast.Assign( )
    tmp.targets = targets
    tmp.value = value
    tmp.lineno = 0
    return tmp

print astnode_genAssign([ast.Name()], ast.Num())