Traceback (most recent call last):
  File "/home/osboxes/mininet/custom/SimpleTreeTopo.py", line 25, in <module>
    net = Mininet(topo)
  File "/usr/local/lib/python3.10/dist-packages/mininet/net.py", line 178, in __init__
    self.build()
  File "/usr/local/lib/python3.10/dist-packages/mininet/net.py", line 508, in build
    self.buildFromTopo( self.topo )
  File "/usr/local/lib/python3.10/dist-packages/mininet/net.py", line 489, in buildFromTopo
    self.addSwitch( switchName, **params )
  File "/usr/local/lib/python3.10/dist-packages/mininet/net.py", line 266, in addSwitch
    sw = cls( name, **defaults )
  File "/usr/local/lib/python3.10/dist-packages/mininet/node.py", line 1105, in __init__
    Switch.__init__( self, name, **params )
  File "/usr/local/lib/python3.10/dist-packages/mininet/node.py", line 927, in __init__
    self.dpid = self.defaultDpid( dpid )
  File "/usr/local/lib/python3.10/dist-packages/mininet/node.py", line 946, in defaultDpid
    raise Exception( 'Unable to derive default datapath ID - '
Exception: Unable to derive default datapath ID - please either specify a dpid or use a canonical switch name such as s23.