def checkpassword_dict(user_password_dict):
    """Returns a checkpassword function which checks credentials
    against a dictionary of the form: {username : password}.

    If you want a simple dictionary-based authentication scheme, use
    checkpassword_dict(my_credentials_dict) as the value for the
    checkpassword argument to basic_auth().
    """
    def checkpassword(realm, user, password):
        p = user_password_dict.get(user)
        return p and p == password or False

    return checkpassword