def _populate_commands(self):
        """ Create an instance of each of the debugger
        commands. Commands are found by importing files in the
        directory 'command'. Some files are excluded via an array set
        in __init__.  For each of the remaining files, we import them
        and scan for class names inside those files and for each class
        name, we will create an instance of that class. The set of
        DebuggerCommand class instances form set of possible debugger
        commands."""
        from trepan.processor import command as Mcommand
        if hasattr(Mcommand, '__modules__'):
            return self.populate_commands_easy_install(Mcommand)
        else:
            return self.populate_commands_pip(Mcommand)