code: def load_gffutils_db(f):
      
      import gffutils
      db = gffutils.FeatureDB(f, keep_order=True)
      return db
docs: Load database for gffutils. 
  
      Parameters
      ----------
      f : str
          Path to database.
  
      Returns
      -------
      db : gffutils.FeatureDB
          gffutils feature database.