Python code issue with spec limit which is NULL

Hello everyone,

I am trying to plot boxplot in Python View together with the spec limits. I encountered problem when some of the parameters come with no specs because a line with ‘missing’ would appear on my graph.

For parameters which are with no specs, I do not want any lines to appear on my graph-- May I know if there is a way to resolve this ?

This is the code that I am using to generate my chart,

Thank you !

Best,

C.D