code: def __find_command_ns(self, command):
          
          # Look for the spaces where the command name appears
          namespaces = []
          for namespace, commands in self._commands.items():
              if command in commands:
                  namespaces.append(namespace)
  
          # Sort name spaces
          namespaces.sort()
  
          # Default name space must always come first
          try:
              namespaces.remove(DEFAULT_NAMESPACE)
              namespaces.insert(0, DEFAULT_NAMESPACE)
          except ValueError:
              # Default name space wasn't present
              pass
  
          return namespaces
docs: Returns the name spaces where the given command named is registered.
          If the command exists in the default name space, the returned list will
          only contain the default name space.
          Returns an empty list of the command is unknown
  
          :param command: A command name
          :return: A list of name spaces