PyYAML 6.0 load() function requires Loader argument

When using an updated version of pyyaml (version 6.0) on Google Colab, there is an import problem in some of Google Colab python packages, like plotly.express:

---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-19-86e89bd44552> in <module>()
----> 1 import plotly.express as px

9 frames
/usr/local/lib/python3.7/dist-packages/plotly/express/__init__.py in <module>()
     13     )
     14 
---> 15 from ._imshow import imshow
     16 from ._chart_types import (  # noqa: F401
     17     scatter,

/usr/local/lib/python3.7/dist-packages/plotly/express/_imshow.py in <module>()
      9 
     10 try:
---> 11     import xarray
     12 
     13     xarray_imported = True

/usr/local/lib/python3.7/dist-packages/xarray/__init__.py in <module>()
      1 import pkg_resources
      2 
----> 3 from . import testing, tutorial, ufuncs
      4 from .backends.api import (
      5     load_dataarray,

/usr/local/lib/python3.7/dist-packages/xarray/tutorial.py in <module>()
     11 import numpy as np
     12 
---> 13 from .backends.api import open_dataset as _open_dataset
     14 from .backends.rasterio_ import open_rasterio as _open_rasterio
     15 from .core.dataarray import DataArray

/usr/local/lib/python3.7/dist-packages/xarray/backends/__init__.py in <module>()
      4 formats. They should not be used directly, but rather through Dataset objects.
      5 
----> 6 from .cfgrib_ import CfGribDataStore
      7 from .common import AbstractDataStore, BackendArray, BackendEntrypoint
      8 from .file_manager import CachingFileManager, DummyFileManager, FileManager

/usr/local/lib/python3.7/dist-packages/xarray/backends/cfgrib_.py in <module>()
     14     _normalize_path,
     15 )
---> 16 from .locks import SerializableLock, ensure_lock
     17 from .store import StoreBackendEntrypoint
     18 

/usr/local/lib/python3.7/dist-packages/xarray/backends/locks.py in <module>()
     11 
     12 try:
---> 13     from dask.distributed import Lock as DistributedLock
     14 except ImportError:
     15     DistributedLock = None

/usr/local/lib/python3.7/dist-packages/dask/distributed.py in <module>()
      1 # flake8: noqa
      2 try:
----> 3     from distributed import *
      4 except ImportError:
      5     msg = (

/usr/local/lib/python3.7/dist-packages/distributed/__init__.py in <module>()
      1 from __future__ import print_function, division, absolute_import
      2 
----> 3 from . import config
      4 from dask.config import config
      5 from .actor import Actor, ActorFuture

/usr/local/lib/python3.7/dist-packages/distributed/config.py in <module>()
     18 
     19 with open(fn) as f:
---> 20     defaults = yaml.load(f)
     21 
     22 dask.config.update_defaults(defaults)

TypeError: load() missing 1 required positional argument: 'Loader

When reverting back to pyyaml version 5.4.1, the problem is solved.

[aigarius]

Yeah, that is not a good solution at all. Breaking 100% of old code is worse than breaking 0.5% of old code that is depending on some of the insecure functionality of the old default loader. Just default to a secure loader as the new default. It is a breaking change, but nowhere near as breaking as this.

The worst is when I have several different packages in my downstream dependencies using PyYAML and some use the new functionality and declare the PyYAML 6 as dependency while others do not provide a loader object to load and just crash now.

Change the PyYAML tutorial for the new syntax at least and let that be up for three years, maybe then it would be ok as a change. But a less destruictive change is always better than more destructive one.

[2sn]

I find it disappoint, however, that the documentation tutorial examples do not work https://pyyaml.org/wiki/PyYAMLDocumentation

import yaml
>>> yaml.load("""
... - Hesperiidae
... - Papilionidae
... - Apatelodidae
... - Epiplemidae
... """)