[Bug Report] FutureWarning: np.object is deprecated in NumPy 1.20+

[1160054]

Link to the notebook
bias-detection-explanability/fairness_and_explainability.ipynb

Describe the bug
When running the script with NumPy 1.20+, an AttributeError occurs due to the removal of np.object.
This happens in the number_encode_features() function when checking column data types:

if result.dtypes[column] == np.object:

Since np.object was deprecated in NumPy 1.20 and completely removed in later versions, this check causes an error.

To reproduce

1. Use a Python environment with NumPy 1.20 or later.
2. Run the script that calls number_encode_features().
3. The following error will be raised:

AttributeError: module 'numpy' has no attribute 'object'

Logs
When executing the script, a FutureWarning might appear before the error occurs:

/tmp/ipykernel_596/1535508334.py:8: FutureWarning: In the future `np.object` will be defined as the corresponding NumPy scalar.
  if result.dtypes[column] == np.object:

Then, the script will fail with:

/tmp/ipykernel_596/1535508334.py:8: FutureWarning: In the future `np.object` will be defined as the corresponding NumPy scalar.
  if result.dtypes[column] == np.object:

AttributeError: module 'numpy' has no attribute 'object'.
`np.object` was a deprecated alias for the builtin `object`. To avoid this error in existing code, use `object` by itself.