import re

content = open('gallery.html', 'r', encoding='utf-8').read()

tabs = re.search(r'<div class="gallery-tabs".*?</div>', content, flags=re.DOTALL)
print("TABS:")
if tabs:
    print(tabs.group(0))

grid = re.search(r'<div class="gallery-grid".*?</div>\s*</div>', content, flags=re.DOTALL)
print("GRID:")
if grid:
    print(grid.group(0)[:500])