- import re  
- l = ["42. blabla \n foo", "42 blabla \n foo", "422. blabla \n foo"] 
- regex_header = re.compile(r"^\d+(?![.\d])") 
- for s in l: 
-     if (regex_header.search(s)): 
-     	print(s) 
				aW1wb3J0IHJlIApsID0gWyI0Mi4gYmxhYmxhIFxuIGZvbyIsICI0MiBibGFibGEgXG4gZm9vIiwgIjQyMi4gYmxhYmxhIFxuIGZvbyJdCnJlZ2V4X2hlYWRlciA9IHJlLmNvbXBpbGUociJeXGQrKD8hWy5cZF0pIikKZm9yIHMgaW4gbDoKICAgIGlmIChyZWdleF9oZWFkZXIuc2VhcmNoKHMpKToKICAgIAlwcmludChzKQ==