Load comments

How do I load (and dump) comments? In the following code, how can I print out the first comment?

import yaml

code = '''# The following key opens a door
key: value
# this is another comment'''

loaded = yaml.load(code)
# CODE HERE: How to print out 'The following key opens a door'?

[yaaraze]

Yaml is used many times as a compromise between readability for users and code. Comments, ordered dicts and other things are an important part of what makes yaml comfortable. In many cases, we use pyYaml to edit existing Yamls. We really need to be able to preserve comments.

[zhujinhe]

There are scenarios where we need to update only specific values, and try not to change anything else as much as possible. Something works like sed or vim is most expected. Hope this feature can be implemented.