In the workflow schema, change items to be of type string.

arguments:
type: array
items:
oneOf:

• type: string
• type: object
  properties:
  lfn:
  type: string
  required:
• lfn
  additionalProperties: false
  minItems: 0

In the python api, when a user does:

f1 = File("f1.txt")
job.add_args("-i", f1)

The underlying arguments field should just be ["-i", "f1.txt"] when the job is serialized.