lines = """line 1
line 2
line 3
line 4
line 5
line 6"""
import re
print re.match(r'(.*)(?=\n{2})', lines, re.DOTALL).groups()
bGluZXMgPSAiIiJsaW5lIDEKbGluZSAyCmxpbmUgMwoKbGluZSA0ICAgIApsaW5lIDUKbGluZSA2IiIiCgppbXBvcnQgcmUKCnByaW50IHJlLm1hdGNoKHInKC4qKSg/PVxuezJ9KScsIGxpbmVzLCByZS5ET1RBTEwpLmdyb3Vwcygp