sub format_phone {
  my @out = @_;
  foreach (@out){
    tr/a-cA-C/2/; tr/d-fD-F/3/; # change letters to digits.
    tr/g-iG-I/4/; tr/j-lJ-L/5/;
    tr/m-oM-O/6/; tr/p-sP-S/7/;
    tr/t-vT-V/8/; tr/w-zW-Z/9/;
    s/[^\d]//g;                 # remove non-digits.
    s/^1//g;                    # remove first digit if it's a one.
    $_ = pack( 'A10', $_ );     # Only take the first ten digits.
  }
  return wantarray ? @out : $out[0];
}