code: def set_l2cap_mtu (sock, mtu):
      
      options = get_l2cap_options (sock)
      options[0] = options[1] = mtu
      set_l2cap_options (sock, options)
docs: set_l2cap_mtu (sock, mtu)
  
      Adjusts the MTU for the specified L2CAP socket.  This method needs to be
      invoked on both sides of the connection for it to work!  The default mtu
      that all L2CAP connections start with is 672 bytes.
  
      mtu must be between 48 and 65535, inclusive.