`HyperparameterNotFoundError` prohibits `.get` from functioning as expected

I am not very familiar with the project, but I came upon this and it looks to me like an oversight (given the refactor of search space to behave more dict-like).

The use of the custom HyperparameterNotFoundError instead of a KeyError breaks the inherited logic of get:

816         def get(self, key, default=None):
817             'D.get(k[,d]) -> D[k] if k in D, else d.  d defaults to None.'
818             try:
819                 return self[key]
820             except KeyError:
821                 return default

Since line 819 fails with a HyperparameterNotFoundError, the .get call now fails if the key is missing from the search space. I recon the easiest would be to derive the custom error from a KeyError, but I don't know what other implications this would have for the project.

MWE:

from ConfigSpace import ConfigurationSpace

cs = ConfigurationSpace(
    name="myspace",
    space={
        "a": (0.1, 1.5),  # UniformFloat
        "b": (2, 10),  # UniformInt
        "c": ["mouse", "cat", "dog"],  # Categorical
    },
)

cs.get("a")  # Correctly gets the UniformFloat
cs.get("d")  # gets output below

>>> cs.get("d")
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/Library/Frameworks/Python.framework/Versions/3.10/lib/python3.10/_collections_abc.py", line 819, in get
    return self[key]
  File "/Users/pietergijsbers/repositories/gama/venv/lib/python3.10/site-packages/ConfigSpace/configuration_space.py", line 1139, in __getitem__
    raise HyperparameterNotFoundError(key, space=self)
ConfigSpace.exceptions.HyperparameterNotFoundError: Hyperparameter d not found in space.
Configuration space object:
  Hyperparameters:
myspace
    a, Type: UniformFloat, Range: [0.1, 1.5], Default: 0.8
    b, Type: UniformInteger, Range: [2, 10], Default: 6
    c, Type: Categorical, Choices: {mouse, cat, dog}, Default: mouse

workaround

dict(cs).get("d")

automl / ConfigSpace

`HyperparameterNotFoundError` prohibits `.get` from functioning as expected #348