wanted: regex or code to find valide def statements in a line

[snippsat]

You could have tried something yourself,maybe you have not started looked into regex as mention before
Here some quick test of something that may work or changed a little,depends on input text.

import re

text = '''\
def my_game():
    print('Game running')

def 123

def foo(arg):
    pass

def Bar(args*, kwargs**):
    pass

hello def is nice
def () wrong'''

# Make list of match
def_name = re.findall(r"def\s(\w+)\(.*", text)
def_line = re.findall(r"def\s\w+\(.*", text)

# Iterate over matches group() or group(1)
matches = re.finditer(r"def\s(\w+)\(.*", text)
for match in matches:
    print(match.group(1))

Output:
my_game
foo
Bar
>>> 
>>> def_name
['my_game', 'foo', 'Bar']
>>>
>>> def_line
['def my_game():', 'def foo(arg):', 'def Bar(args*, kwargs**):']
>>>