use feature qw(state);
  use Type::Params 1.004000 qw(compile_named);
  use Types::Standard qw(FileHandle HasMethods Str Object);
  
  sub htmlprint {
    state $check = compile_named(
      file   => FileHandle | HasMethods['printf'],
      text   => Str,
      colour => Str, { default => "black" },
    );
    my $self = Object->(shift);  # will die if it's not an object
    my $arg  = $check->(@_);
    
    ...;  # rest of the function goes here
  }