class_docstr: List of ports
  
  For use configuring a list of ports to consume
  
  Ports will be a list of valid ports
  
  Can be specified as a port-range string for convenience
  (mainly for use on the command-line)
  e.g. '10101-10105,10108'
code: def from_string_list(self, s_list):
      ports = []
      for s in s_list:
          ports.extend(self.parse_port_range(s))
      return ports
  
file_path: ipyparallel/ipyparallel/traitlets.py
imports: import entrypoints
  from traitlets import List, TraitError, Type
label_desc: Use image node_id 2 for calling the PortList obj's underlying member method code with example usage: obj.from_string_list(s_list) and returns: ports