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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def pre_build(self, user, install_path, variants=None, release_message=None, changelog=None, previous_version=None, previous_revision=None, **kwargs):
 """Pre-build hook. Args: user: Name of person who did the release. install_path: Directory the package was installed into. variants: List of variant indices we are attempting to build, or None release_message: User-supplied release message. changelog: List of strings describing changes since last release. previous_version: Version object - previously-release package, or None if no previous release. previous_revision: Revision of previously-released package (type depends on repo - see ReleaseVCS.get_current_revision(). kwargs: Reserved. Note: This method should raise a `ReleaseHookCancellingError` if the release process should be cancelled. """

        pass