import re


def is_cusip(value):
    """Checks whether a string is a valid CUSIP identifier.

    Regex from here: https://regex101.com/r/vN3tE5/1

    :param value: A string to evaluate.
    :returns: True if string is in the form of a valid CUSIP number."""
    return re.match(r'^([\w\d]{6})([\w\d]{2})([\w\d]{1})$', value)