code: def _sincedb_init(self):
          
          if not self._sincedb_path:
              return
  
          if not os.path.exists(self._sincedb_path):
              self._log_debug('initializing sincedb sqlite schema')
              conn = sqlite3.connect(self._sincedb_path, isolation_level=None)
              conn.execute("""
              create table sincedb (
                  fid      text primary key,
                  filename text,
                  position integer default 1
              );
              """)
              conn.close()
docs: Initializes the sincedb schema in an sqlite db