Bug fix for parse dataest definition

[noklam]

NOTE: Kedro datasets are moving from kedro.extras.datasets to a separate kedro-datasets package in
kedro-plugins repository. Any changes to the dataset implementations
should be done by opening a pull request in that repository.

Description

#3272 introduce an unexpected bug. #3369 is the original PR that try to address this.

The actual problem is that we accidentally drop the support of type: PythonClass (we never officially support it). In our docs we always expect it to support the following 3 cases. The decision is to not make any behavior change and we will add documentations and tests to support this.

dataset: Underlying dataset definition. This is used to instantiate
the dataset for each file located inside the path.
Accepted formats are:
a) object of a class that inherits from AbstractDataset
b) a string representing a fully qualified class name to such class
c) a dictionary with type key pointing to a string from b),

Development notes

• add tests to support the change explicitly
• add documentations.

How to test

1. clone this branch and install it.
2. run kedro-datasets tests.

If you running this on GitPod, you need some extra instruction to run datasets tests.

sudo apt-get install -y --no-install-recommends libatk-bridge2.0-0 libcups2 ca-certificates fonts-liberation libasound2 libatk-bridge2.0-0 libatk1.0-0 libc6 libcairo2 libcups2 libdbus-1-3 libexpat1 libfontconfig1 libgbm1 libgcc1 libglib2.0-0 libgtk-3-0 libnspr4 libnss3 libpango-1.0-0 libpangocairo-1.0-0 libstdc++6 libx11-6 libx11-xcb1 libxcb1 libxcomposite1 libxcursor1 libxdamage1 libxext6 libxfixes3 libxi6 libxrandr2 libxrender1 libxss1 libxtst6 lsb-release wget xdg-utils
sudo apt-get update && sudo apt-get install -y --no-install-recommends libgl1

I opened a separate PR to fix the gitpod docker to automate this.

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Checklist

• Read the contributing guidelines
• Signed off each commit with a Developer Certificate of Origin (DCO)
• Opened this PR as a 'Draft Pull Request' if it is work-in-progress
• Updated the documentation to reflect the code changes
• Added a description of this change in the RELEASE.md file
• Added tests to cover my changes
• Checked if this change will affect Kedro-Viz, and if so, communicated that with the Viz team

[merelcht]

Thanks Nok! ⭐

[AhdraMeraliQB]

Tested manually and did not run into any UnboundLocalError, thanks for the fix!