Message4997

Assignment of a newly created ast Node value fails. The assignment
destination become 'None' rather then accepting the value.
Test case:
Simple code mutation. Trying manipulate the ast tree to change a
methods call like
a.set( 1 )
to the assignment:
a = 1
By running attached code 'astMutationTest.py' ('unparse.py' code is
obtained from Cpython parse demo code)
the python output is:
Before Mutation
a.set(1)
After Mutation
a = 1
But for Jython:
Before Mutation
a.set(1)
After Mutation
None