Ok... first problem I see (besides the params regexp already pointed out... is your not_method regexp piece...

you didn't put it in a container, so your pipes aren't doing what you expect...

if ($line =~ /^\W*(?:$not_method)/) {
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That'll work better.

Update a \b at the end would also help make sure you don't match a string starting with as or if etc...

if ($line =~ /^\W*(?:$not_method)\b/) {
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