How to use the webauthn.const.USER_VERIFIED function in webauthn

# Verify that the User Present bit of the flags in authData
            # is set.

            # Authenticator data flags.
            # https://www.w3.org/TR/webauthn/#authenticator-data
            flags = struct.unpack('!B', decoded_a_data[32:33])[0]

            if (flags & const.USER_PRESENT) != 0x01:
                raise AuthenticationRejectedException(
                    'Malformed request received.')

            # Step 13.
            #
            # If user verification is required for this assertion, verify that
            # the User Verified bit of the flags in authData is set.
            if (self.uv_required and (flags & const.USER_VERIFIED) != 0x04):
                raise RegistrationRejectedException(
                    'Malformed request received.')

            # Step 14.
            #
            # Verify that the values of the client extension outputs in
            # clientExtensionResults and the authenticator extension outputs
            # in the extensions in authData are as expected, considering the
            # client extension input values that were given as the extensions
            # option in the get() call. In particular, any extension identifier
            # values in the clientExtensionResults and the extensions in
            # authData MUST be also be present as extension identifier values
            # in the extensions member of options, i.e., no extensions are
            # present that were not requested. In the general case, the meaning
            # of "are as expected" is specific to the Relying Party and which
            # extensions are in use.