code: function listPrivateKey(keyType, folder, name, noRetry) {
      let privateKeyName;
  
      // Try with .key suffix first. If unsuccessful, retry without the .key suffix
      if (noRetry) {
          // If present, remove '.key' suffix
          privateKeyName = name.replace(REG_EXPS.KEY_SUFFIX, '');
      } else {
          // Append '.key' suffix, if not present
          privateKeyName = (name.match(REG_EXPS.KEY_SUFFIX)) ? name : `${name}.key`;
      }
  
      return util.runTmshCommand(`list sys ${keyType} /${folder}/${privateKeyName}`)
          .then((keyData) => {
              // If no result, retry if a retry hasn't occurred yet.
              if (!keyData) {
                  if (!noRetry) {
                      return listPrivateKey(keyType, folder, name, true);
                  }
                  return q();
              }
              return q({ privateKeyName, keyData });
          })
          .catch((err) => {
              // If the object is not found (code: 01020036:3), retry if a retry hasn't occurred yet.
              const notFoundRegex = /01020036:3/;
              if (err.message.match(notFoundRegex) && !noRetry) {
                  return listPrivateKey(keyType, folder, name, true);
              }
              return q.reject(err);
          });
  }
docs: List a private key by folder and name.
  
  Will first search for a private key with a '.key' suffix, and then without a '.key' suffix
  
  @param {String}  keyType      - Key Type to list. Examples: 'file ssl-key', crypto key
  @param {String}  folder       - Folder in which to search for the private key.
  @param {String}  name         - Name of the private key to search for
  @param {Boolean} [noRetry]    - Whether or not to retry command with a different private key name.
  
  @returns {Promise}   A promise which will be resolved with a dictionary containing the name of the
  found private key, and the tmsh command response:
  
  {
  privateKeyName: <String>,
  response: <String>
  }