Adding option to select file types

[lisa-asket]

I have the following bash function and I want an option that allows me

to pass the file type if I do not want the default .org and .texi



-----



print-region ()
  {
    na=$1
    nb=$2
    dir=$3
    
      find "$dir" \( -name \*.org -o -name \*.texi \)  \
        -exec awk -v a="$na" -v b="$nb"                \
              'FNR == 1 {s="\n==> "FILENAME" <==\n"; f = 0}
               FNR == a {print s; f = 1}
               f {print; if (FNR == b) nextfile}' {} +
  }