How can I modify data using a variable field name?

I am trying to create a program that modify different dbf file but since each file have different field name, I am unsure if the python dbf library have the option to specify the field with string.

To modify the data without variable

dbf.write(record, CUSTOM2="Hello")

But when I tried this, it gives an error

dbf.write(record, {'CUSTOM2': "Hello"})

TypeError: write() takes 1 positional argument but 2 were given

There are a couple ways to update records in dbf files:

• use the record as a context manager:

    target_field = 'custom2'
    with record:
        record[target_field] = "Hello"

• or use the write function with keywords:

    target_field = 'custom2'
    update = {target_field: "Hello"}
    dbf.write(record, **update)