code: def __findInstrumentId(self, instrument):
      cursor = self.__connection.cursor()
      sql = "select instrument_id from instrument where name = ?"
      cursor.execute(sql, [instrument])
      ret = cursor.fetchone()
      if ret is not None:
          ret = ret[0]
      cursor.close()
      return ret
  
imports: from pyalgotrade.barfeed import dbfeed
  from pyalgotrade.barfeed import membf
  from pyalgotrade import bar
  from pyalgotrade.utils import dt
  import sqlite3
  import os
label_desc: Use image node_id 2 for calling the Database obj's underlying member method code with example usage: obj.__findInstrumentId(instrument) and returns: ret