>perl -wMstrict -le
"my %families = (
     flintstones => {
         dad => 'fred',
         mom => 'wilma',
         kid => 'bambam',
         },
     simpsons => {
         dad => 'fred',
         mom => 'marge',
         kid => 'bart',
         sis => 'lisa',
         },
     );
 use Test::More 'no_plan';
 my @got;
 is @got = get_members(\%families => kid => 'bart'), 1, 'got bart';
 note qq{families with bart: '@got'};
 is @got = get_members(\%families => dad => 'fred'), 2, 'got freds';
 note qq{families with freds: '@got'};
 is @got = get_members(\%families => mom => 'june'), 0, 'no junes';
 note qq{families with june: '@got'};
 is @got = get_members(\%families => sis => 'lisa'), 1, 'got lisa';
 note qq{families with lisa: '@got'};
 is @got = get_members(\%families => xxx => 'yyy'),  0, 'no xxx';
 note qq{what's an xxx? '@got'};
 sub get_members {
   my ($hr_families, $member, $name) = @_;
   return
     grep $hr_families->{$_}{$member} eq $name,
     grep exists($hr_families->{$_}{$member}),
     keys %$hr_families
     ;
   }
"
ok 1 - got bart
# families with bart: 'simpsons'
ok 2 - got freds
# families with freds: 'simpsons flintstones'
ok 3 - no junes
# families with june: ''
ok 4 - got lisa
# families with lisa: 'simpsons'
ok 5 - no xxx
# what's an xxx? ''
1..5