class Hamster::MutableSet

@api private

def self.[](*items) 

def self.[](*items)
  MutableSet.new(Set[*items])
end

def add(item) 

def add(item)
  transform { |set| set.add(item) }
end

def add?(item) 

def add?(item)
  added = false
  transform do |set|
    added = !set.include?(item)
    set.add(item)
  end
  added
end

def delete(item) 

def delete(item)
  transform { |set| set.delete(item) }
end

def delete?(item) 

def delete?(item)
  deleted = false
  transform do |set|
    deleted = set.include?(item)
    set.delete(item)
  end
  deleted
end