docs: async def is_pairwise_exists(wallet_handle: int,
                               their_did: str) -> bool:
      """
      Check if pairwise is exists.
  
      :param wallet_handle: wallet handler (created by open_wallet).
      :param their_did: encoded Did.
      :return: true - if pairwise is exists, false - otherwise
      """
  
      logger = logging.getLogger(__name__)
      logger.debug("is_pairwise_exists: >>> wallet_handle: %r, their_did: %r",
                   wallet_handle,
                   their_did)
  
      if not hasattr(is_pairwise_exists, "cb"):
          logger.debug("is_pairwise_exists: Creating callback")
          is_pairwise_exists.cb = create_cb(CFUNCTYPE(None, c_int32, c_int32, c_bool))
  
      c_wallet_handle = c_int32(wallet_handle)
      c_their_did = c_char_p(their_did.encode('utf-8'))
  
      res = await do_call('indy_is_pairwise_exists',
                          c_wallet_handle,
                          c_their_did,
                          is_pairwise_exists.cb)
  
      logger.debug("is_pairwise_exists: <<< res: %r", res)
      return res