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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def get_yaml_parser_roundtrip():
 """Create the yaml parser object with this factory method. The round-trip parser preserves: - comments - block style and key ordering are kept, so you can diff the round-tripped source - flow style sequences ( ‘a: b, c, d’) (based on request and test by Anthony Sottile) - anchor names that are hand-crafted (i.e. not of the form``idNNN``) - merges in dictionaries are preserved Returns: ruamel.yaml.YAML object with round-trip loader """

    yaml_writer = yamler.YAML(typ='rt', pure=True)
    # if this isn't here the yaml doesn't format nicely indented for humans
    yaml_writer.indent(mapping=2, sequence=4, offset=2)
    return yaml_writer