Python: Using "map" to update a list of dictionary

[dvas0004]

old_list = [{
   'fieldToUpdate': 'oldValue'
}]

new_list = list( map( lambda entry: entry.update({'fieldToUpdate': 'newValue'}) or entry, old_list) )

# new_list is now: [{'fieldToUpdate': 'newValue'}]

The above code snippet makes use of the fact that the "update" method of a standard python dict returns "None" - hence you can see the "or" being used to returned the newly updated entry