def rev_reg_id2cred_def_id(rr_id: str) -> str:
return '<STR_LIT::>'.join(rr_id.split('<STR_LIT::>')[<NUM_LIT:2>:-<NUM_LIT:2>])<EOL>
Given a revocation registry identifier, return its corresponding credential definition identifier.

:param rr_id: revocation registry identifier
:return: credential definition identifier