Short Answer 
The error ‘SyntaxError: future feature annotations is not defined’ indicates that the Python version in use is older than 3.7, which does not support future feature annotations. To resolve this, users can either upgrade to Python 3.7 or higher, or modify their code to remove these annotations and use compatibility libraries such as ‘future-annotations’.
Step 1: Understand the Error
The error message ‘SyntaxError: future feature annotations is not defined’ arises when utilizing features in a Python version that doesn’t support them. Specifically, this error is linked to the future feature annotations, which were introduced in Python 3.7 and enable forward references in type annotations. Knowing the context of this error is crucial in determining the right solution.
Step 2: Upgrade Your Python Version
If you find yourself operating on Python versions earlier than 3.7, the most straightforward solution is to upgrade to a version that includes support for future feature annotations. This can be done by:
- Visiting the official Python website to download the latest version.
- Using a package manager like pip or conda to handle your upgrade seamlessly.
- Verifying your Python installation via the command line to ensure the upgrade was successful.
Step 3: Modify Your Code or Use Compatibility Libraries
If upgrading Python is not feasible, consider modifying your code. You can remove future feature annotations or apply alternative methods like type comments. Additionally, you can leverage compatibility libraries such as future-annotations that enable the use of these annotations in older versions. You can achieve this by:
- Installing the compatibility library through pip.
- Updating your codebase to utilize the library effectively.
- Consulting the documentation for best practices on implementation.