code: public boolean isDockerMachineInstalled(String cliPathExec) {
          try {
              commandLineExecutor.execCommand(createDockerMachineCommand(cliPathExec));
              return true;
          } catch (Exception e) {
              return false;
          }
      }
docs: Checks if Docker Machine is installed by running docker-machine and inspect the result.
  
  @param cliPathExec
  location of docker-machine or null if it is on PATH.
  
  @return true if it is installed, false otherwise.