module ActiveRecord::Persistence

user.banned? # => true
user.toggle(:banned)
user.banned? # => false
user = User.first

Example:

Returns +self+.
method toggles directly the underlying value without calling any setter.
if the predicate returns +true+ the attribute will become +false+. This
Assigns to +attribute+ the boolean opposite of attribute?. So

def toggle(attribute)
  self[attribute] = !public_send("#{attribute}?")
  self
end