code: def get_ip_netns(self, ip_netns_file):
          
          out = []
          try:
              ip_netns_out = open(ip_netns_file).read()
          except IOError:
              return out
          for line in ip_netns_out.splitlines():
              # If there's no namespaces, no need to continue
              if line.startswith("Object \"netns\" is unknown") \
                 or line.isspace() \
                 or line[:1].isspace():
                  return out
              out.append(line.partition(' ')[0])
          return out
docs: Returns a list for which items are namespaces in the output of
          ip netns stored in the ip_netns_file.