import glob, os, re

def convert(name):
    s1 = re.sub('(.)([A-Z][a-z]+)', r'1_2', name)
    return re.sub('([a-z0-9])([A-Z])', r'1_2', s1).lower()


if __name__ == '__main__':
    dir = 'D:......'
    os.chdir(dir)
    def_list = []
    for file in glob.glob("*.py"):
        f = open(file)
        for line in f:
            wostrip = line.lstrip()
            if wostrip.startswith('def'):
                method_name = wostrip[wostrip.find(' ') + 1:wostrip.find('(')]
                if method_name != convert(method_name):
                    def_list.append((method_name, convert(method_name)))
        end_list = list(set(def_list))
        end_list.sort(key=lambda tup: tup[0])
    for def_ in end_list:
        old_name = def_[0] # старые имена
        new_name = def_[1] # новые имена

filelist = ['filename01', 'filename02']
for filename in filelist:
    with open (filename, 'r') as f:
        old_data = f.read()
    names_map = get_method_names_for_replacement(old_data)
    new_data = old_data
    for old_name in names_map:
        new_data = new_data.replace(old_name, names_map[old_name])
    with open (filename, 'w') as f:
        f.write(new_data)