code: def extraction_error(self):
          
  
          old_exc = sys.exc_info()[1]
          cache_path = self.extraction_path or get_default_cache()
  
          tmpl = textwrap.dedent("""
              Can't extract file(s) to egg cache
  
              The following error occurred while trying to extract file(s)
              to the Python egg cache:
  
                {old_exc}
  
              The Python egg cache directory is currently set to:
  
                {cache_path}
  
              Perhaps your account does not have write access to this directory?
              You can change the cache directory by setting the PYTHON_EGG_CACHE
              environment variable to point to an accessible directory.
              """).lstrip()
          err = ExtractionError(tmpl.format(**locals()))
          err.manager = self
          err.cache_path = cache_path
          err.original_error = old_exc
          raise err
docs: Give an error message for problems extracting file(s)