Add audeer.set_or_delete_env_variable()

[hagenw]

Adds audeer.set_or_delete_env_variable() to set an environment variable to the provided value, or delete it if the value is None. This helper function is quite useful for writing test fixtures that modify environment variables.

Summary by Sourcery

New Features:

• Introduce audeer.set_or_delete_env_variable() to manage environment variables by setting them to a given value or deleting them if the value is None.

[sourcery-ai]

Reviewer's Guide by Sourcery

This PR introduces a new utility function set_or_delete_env_variable() in the audeer library that provides a convenient way to manage environment variables. The function is implemented as a simple wrapper around os.environ operations, allowing both setting and deletion of environment variables based on the provided value.

No diagrams generated as the changes look simple and do not need a visual representation.

File-Level Changes

Change	Details	Files
Added a new utility function to manage environment variables	Implemented function to set environment variable when value is provided Added logic to delete environment variable when value is None Added function documentation with clear parameter descriptions	audeer/core/utils.py

---

Tips and commands

Interacting with Sourcery

• Trigger a new review: Comment @sourcery-ai review on the pull request.
• Continue discussions: Reply directly to Sourcery's review comments.
• Generate a GitHub issue from a review comment: Ask Sourcery to create an
  issue from a review comment by replying to it.
• Generate a pull request title: Write @sourcery-ai anywhere in the pull
  request title to generate a title at any time.
• Generate a pull request summary: Write @sourcery-ai summary anywhere in
  the pull request body to generate a PR summary at any time. You can also use
  this command to specify where the summary should be inserted.

Customizing Your Experience

Access your dashboard to:

• Enable or disable review features such as the Sourcery-generated pull request
  summary, the reviewer's guide, and others.
• Change the review language.
• Add, remove or edit custom review instructions.
• Adjust other review settings.

Getting Help

• Contact our support team for questions or feedback.
• Visit our documentation for detailed guides and information.
• Keep in touch with the Sourcery team by following us on X/Twitter, LinkedIn or GitHub.