Function registers into self.commands from module.

        Args
        ----
          module (module): The module name.

def register(self, module):
        """
        Function registers into self.commands from module.

        Args
        ----
          module (module): The module name.
        """
        if module is not None:
            cmds = self.retrieve_commands(module)

            for c in cmds:
                if self.valid_name(c.name):
                    cmd = c(self.subparsers)
                    self.commands.append(cmd)
                else:
                    print(colored("Warning: Command %s has empty name. It won't be registered"
                                  % c, 'yellow'))