import re
def has_pattern(string, regex):
    if string and re.compile(regex).search(string) is not None:
        return True
    return False

# for absolute path on windows
pattern = '^[a-zA-Z]:\\[^\\]' # actual regex: [a-zA-Z]:\[^\]
path = 'a:\' # for this result should be 'True'
print('Pattern: '{0}''.format(pattern))
print('Result: {0}'.format(has_pattern(path, pattern)))