code: public ArrayList<PinCapability> getPinCapabilities(Integer pin) {
          if (pinCapabilities.size() >= pin) {
              return pinCapabilities.get(pin);
          }
          return null;
      }
docs: Get Pin Capabilities
  Get a list of modes that a given pin supports.
  @param pin Integer value representing the Firmata pin that we want to know the supported capabilities of.
  @return ArrayList of PinCapability that the given pin index supports.\
  Null if there is no pin at the given index.