code: func (m *MCP23017Driver) SetPullUp(pin uint8, val uint8, portStr string) error {
  	selectedPort := m.getPort(portStr)
  	return m.write(selectedPort.GPPU, pin, val)
  }
docs: // SetPullUp sets the pull up state of a given pin based on the value:
  // val = 1 pull up enabled.
  // val = 0 pull up disabled.