code: def find_store_dirs(cls):
          
          store_dirs = [default_store_location()]
          extra_dirs_str = os.getenv('QUILT_PACKAGE_DIRS')
          if extra_dirs_str:
              store_dirs.extend(extra_dirs_str.split(':'))
          return store_dirs
docs: Returns the primary package directory and any additional ones from QUILT_PACKAGE_DIRS.