<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def get_claimed_username(token):
 """ Given a JWT, get the username that it is claiming to be `without verifying that the signature is valid`. :param token: JWT claim :return: Username """

    unverified_data = jwt.decode(token, options={
        'verify_signature': False
    })

    if 'username' not in unverified_data:
        return None
    return unverified_data['username']