class_docstr: A data class to store a list of HostInfo objects.
code: def __len__(self):
      return len(self.hostinfo_list)
  
file_path: colossalai/colossalai/cli/launcher/hostinfo.py
imports: import socket
label_desc: Use image node_id 7 for calling the HostInfoList obj's underlying member method code with example usage: obj.__len__() and returns: len