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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 async def jsk_debug(self, ctx: commands.Context, *, command_string: str):
 """ Run a command timing execution and catching exceptions. """


        alt_ctx = await copy_context_with(ctx, content=ctx.prefix + command_string)

        if alt_ctx.command is None:
            return await ctx.send(f'Command "{alt_ctx.invoked_with}" is not found')

        start = time.perf_counter()

        async with ReplResponseReactor(ctx.message):
            with self.submit(ctx):
                await alt_ctx.command.invoke(alt_ctx)

        end = time.perf_counter()
        return await ctx.send(f"Command `{alt_ctx.command.qualified_name}` finished in {end - start:.3f}s.")