s = """('Vdfbr76','gsdf','gsfd','',NULL),
('Vkdfb23l','gsfd','gsfg','ggg@df.gf',NULL),
('4asg0124e','Lead Actor/SFX MUA/Prop designer','John Smith','jsmith@email.com',NULL),
('asdguIux','Director, Camera Operator, Editor, VFX','John Smith','',NULL),
(492,'E1asegaZ1ox','Nysdag_5YmD','145872325372620',1,'long, string, with, commas'),
"""
for line in s.split('\n'):
    line = line.strip().rstrip(',').replace('NULL', 'None')
if line:
    pass
Динамическое разделение сложных строк в Python