map-and-reduce.md: code in Pluck challenge throws TypeError

[wmotion]

In the exercise https://esciencecenter-digital-skills.github.io/parallel-python-workbench/instructor/map-and-reduce.html#challenge-consider-pluck

the verbatim code

from dask import bag as db
  
data = [
     { "name": "John", "age": 42 },
     { "name": "Mary", "age": 35 },
     { "name": "Paul", "age": 78 },
     { "name": "Julia", "age": 10 }
  ]

bag = db.from_sequence(data)

bag.map(partial(getitem,"name")).compute()

throws

  TypeError: string indices must be integers