how to build a dropdown that contains readable access groups?

i am building a filter that allows users to filter entity lists according to the access level of the entities.. 

in looking through access.php i see that there is a suitable function for write levels (http://reference.elgg.org/engine_2lib_2access_8php.html#a1ddaf14e1625a4f84a4cf95615f0226f) , but not read levels:

http://reference.elgg.org/engine_2lib_2access_8php.html#a6dd352b6343cd157d34dc6d2dae79a9d


get_access_array returns the ids, but not the labels..

do i need to write my own function?

thanks