# instead of
my $class = shift;
my $self = bless {}, ref($class) || $class;
# try
my $self = bless {}, ref($_[0]) || @_

##</code><code>##

sub foo {
   # some stuff
   open my $fh, @_;
   return $fh;
}

##</code><code>##

sub foo {
   # some stuff
   my $fh;
   if (@_ == 1) {
      open $fh, $_[0];
   } else {
      open $fh, $_[0], $_[1], @_[2..$#_];
   }
   return $fh;
}