gistfile1.py

def match(fns):
  def inner(x):
    for cls, fn in fns:
      if isinstance(x, cls):
        return fn(x)

  return inner

doformat = match(
  [ (Literal, lambda x: x)
  , (AllOf:   lambda x: ' and '.join(doformat(y) for y in x))
  , (Enum:    lambda x: ....)
  ])

doformat(root)