def get_source_files(self) -> List[str]:
        """
        Return a list of all files that are used by the command to create the expected
        outputs.
        For example, if your build command transpiles Java files into Python, you should
        list here all the Java files.
        The primary purpose of this function is to help populating the ``sdist``
        with all the files necessary to build the distribution.
        All files should be strings relative to the project root directory.
        """

        Return a list of all files that are used by the command to create the expected
        outputs.
        For example, if your build command transpiles Java files into Python, you should
        list here all the Java files.
        The primary purpose of this function is to help populating the ``sdist``
        with all the files necessary to build the distribution.
        All files should be strings relative to the project root directory.
        
product/gradle-plugin/src/main/python/setuptools/command/build.py