def check_subscriber_hash(potential_hash):
if re.match(r"<STR_LIT>", potential_hash):<EOL><INDENT>return potential_hash<EOL><DEDENT>else:<EOL><INDENT>return get_subscriber_hash(potential_hash)<EOL><DEDENT>
Check the passed value to see if it matches a 32 character hex number that
MD5 generates as output, or compute that value assuming that the input is
an email address.

:param potential_hash: A value to be passed to any of the endpoints that
expect an MD5 of an email address
:type potential_hash: :py:class:`str`
:returns: A valid MD5 hash in hex
:rtype: :py:class:`str`