Split mysql dump to multiple files by database (python3)

mysql_split.py

import sys, re

fileName = sys.argv[1]
with open(fileName, 'r', encoding='utf-8') as f:
    firstSection = ''
    currentFile = None
    for line in f:
        if line.startswith('CREATE DATABASE'):
            if currentFile:
                currentFile.close()
            currentDatabase = re.search('`(.*?)`', line).group(1).strip()
            currentFile = open(fileName + '_' + currentDatabase + '.sql', 'w', encoding='utf-8')
            currentFile.write('-- Mysql Dump Splitter by Egor Aristov (c) 2019 efprojects.com\n\n')
            currentFile.write(firstSection)
            currentFile.write(line)
        else:
            if currentFile:
                currentFile.write(line)
            else:
                firstSection += line

    if currentFile:
        currentFile.close()