[fix](cli): handle edge cases with empty NUMA nodes

[Andy18650]

What does this PR do?

When the system contains a NUMA node without any cores, the _parse_cpu_list() function crashes with the following error:

ValueError: invalid literal for int() with base 10: ''

This fix adds edge-case handling by returning an empty list. Further processing downstream will treat the return value as one single NUMA node, which is expected behavior.

Technical background

Empty NUMA nodes appear on systems with Intel's Optane DCPMM modules. In standard Memory Mode, some system DRAM is used as a transparent direct-mapped cache for Optane modules, and thus will be considered one NUMA node per socket. In this case, the DRAM capacity is "absorbed" into that of Optane (for example, 64GiB DRAM+256GiB Optane = 256GiB visible to system, minus some overhead). However, there is also a technique to expand system RAM with Optane Modules by setting them to App Direct mode and them mapping them as memory on a virtual NUMA node with daxctl. This enables the capacity of DRAM and Optane to be presented as separate memory regions. Furthermore, this enables advanced LRU-based page promotion and demotion algorithm to be used.

Before submitting

• Did you read the contributor guideline?
• Did you write any new necessary tests? N/A

[gemini-code-assist]

Code Review

This pull request updates the _parse_cpu_list utility function to handle empty input strings, which occurs when a NUMA node has no assigned CPU cores. The reviewer suggested using a more idiomatic Python check for the empty string and improving the grammar of the accompanying comment.

[gemini-code-assist]

Using if not cpulist: is more idiomatic in Python for checking empty strings and also handles None values gracefully. Additionally, the comment should be capitalized and punctuated correctly for better readability.

Suggested change

	if cpulist == "":
	# if there are no cpu cores for a specific numa node (for example, virtual numa on optane), return empty list
	return cpus
	if not cpulist:
	# If there are no CPU cores for a specific NUMA node (e.g., virtual NUMA on Optane), return an empty list.
	return []

[yyj6666667]

Good catch on the edge case, with one line to save them all. Many thanks.