Excel macro: Last non-empty cell in a column [duplicate]

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• Error Finding Last Used cell In VBA 4 answers

This is a followup question to this one.

The following formula can be used to find the value of the last non-empty cell in a column, in Microsoft Excel:

=LOOKUP(2,1/(A:A<>""),A:A)

My question is, how can I convert this formula to a Macro function? So that I can use it like this:

=GetLastValueInColumn('A')

Indeed, I need to convert the letter 'A' to range A:A, but don't know how.