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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 cache_distribution(cls, zf, source, target_dir):
 """Possibly cache an egg from within a zipfile into target_cache. Given a zipfile handle and a filename corresponding to an egg distribution within that zip, maybe write to the target cache and return a Distribution."""

    dependency_basename = os.path.basename(source)
    if not os.path.exists(target_dir):
      target_dir_tmp = target_dir + '.' + uuid.uuid4().hex
      for name in zf.namelist():
        if name.startswith(source) and not name.endswith('/'):
          zf.extract(name, target_dir_tmp)
      os.rename(os.path.join(target_dir_tmp, source),
                os.path.join(target_dir_tmp, dependency_basename))

      rename_if_empty(target_dir_tmp, target_dir)

    dist = DistributionHelper.distribution_from_path(target_dir)
    assert dist is not None, 'Failed to cache distribution %s' % source
    return dist