Adding comments to dumped python classes

[the-moog]

Line 830 of representer.py hints that it's possible to add comments to serialisation of python object instances.

Consider the following code. How would I modify it so that the resulting yaml is commented to look like this:

!C
# Documentation for  class C
data: C
contents: !B
# Documentation for class B
  data: B
  contents: !A
# Documentation for class A
    data: A
    contents:

Is that already possible or would that be a new feature?

import ruamel.yaml
from ruamel.yaml import yaml_object
from io import StringIO
import contextlib
import sys


@contextlib.contextmanager
def uncloseable(fd):
    """
    Context manager which turns the fd's close operation to no-op for the duration of the context.
    """
    close = fd.close
    fd.close = lambda: None
    yield fd
    fd.close = close


def get_obj_as_yaml(yaml_inst, object):
    # Use StringIO to capture the yaml output
    s = StringIO()
    with uncloseable(s):
        yaml_inst.dump(object, s)

    yaml_text = s.getvalue()
    s.close()
    return yaml_text


yaml = ruamel.yaml.YAML()

class SomeData:
    def __init__(self, data):
        self.data = data
        self.contents = None

@yaml_object(yaml)
class A(SomeData):
    """This is an A object"""
    def __init__(self):
        super().__init__("A")


@yaml_object(yaml)
class B(SomeData):
    """This is a B object"""
    def __init__(self):
        super().__init__("B")
        self.contents = A()


@yaml_object(yaml)
class C(SomeData):
    """This is a C object"""
    def __init__(self):
        super().__init__("C")
        self.contents = B()


# Create an instance of the top level object
# which has other object instances inside
instance = C()

# Serialise the objects tree as yaml
text = get_obj_as_yaml(yaml, instance)
sys.stdout.write(text)