class Hamster::SortedSet::AVLNode::Empty

def at(index); nil; end

def between(from, to);       self; end

def bulk_delete(items); self; end

def bulk_insert(items)
  items = items.to_a if !items.is_a?(Array)
  AVLNode.from_items(items.sort(&@comparator), @comparator)
end

def delete(item);       throw :not_present; end

def drop(n);             self; end

def each;           end

def each_between(item, inclusive); end

def each_greater(item, inclusive); end

def each_less(item, inclusive);    end

def empty?;              true; end

def height;   0;    end

def include?(item);     false; end

def initialize(comparator); @comparator = comparator; end

def insert(item)
  AVLNode.new(item, @comparator, self, self)
end

def keep_only(items);   self; end

def left;  self;    end

def max;    nil;    end

def min;    nil;    end

def natural_order?; false; end

def prefix(item, inclusive); self; end

def reverse_each;   end

def right; self;    end

def size;     0;    end

def slice(from, length); self; end

def suffix(item, inclusive); self; end

def take(n);             self; end