Last 7 Days Data Based on a Parameter

= Table.SelectRows(#"Set Data Types", let latest = List.Max(#"Set Data Types"[Gas Day]) in each ([Gas Day] <= latest) and ([Gas Day] >= Date.AddDays(latest,- 7) ))

Hi All

I found the above code to filter my date field in Power Query for the last 7 days in my data

What I would like to do is change that to the last 7 days from the date set in a Parameter

I have got as far as creating a Parameter called Gas Day Executed On and placed it in my code below

= Table.SelectRows(#"Set Data Types", let latest = #"Gas Day Executed") in each ([Gas Day] <= latest) and ([Gas Day] >= Date.AddDays(latest,- 7) ))

This gives me an error

Can any help me get this working, much appreciated!