docs: function(callback) {
  
    if (isProviderUp) {
  
      // All is good!
      return Promise.resolve()
      .nodeify(callback);
  
    } else {
  
      // Query for provider's up status.
      return providerInstance().call('isUp')
      // Update cache and turn on provider if needed
      .then(function(isUp) {
        isProviderUp = isUp;
        if (!isProviderUp) {
          // Try to turn it on!
          return up()
          // Turn promise resolution
          .then(function() {
            return Promise.resolve();
          });
        }
      })
      // Return.
      .nodeify(callback);
  
    }
  
  }