module ActiveRecord::Validations

some :on option will only run in the specified context.
\Validations with no :on option will run no matter the context. \Validations with

run within multiple contexts.
If the argument is an array of contexts, post.valid?([:create, :update]), the validations are
{new_record?}[rdoc-ref:Persistence#new_record?] is +true+, and to :update if it is not.
If the argument is +false+ (default is +nil+), the context is set to :create if

Aliased as #validate.

no errors are found, +false+ otherwise.
Runs all the validations within the specified context. Returns +true+ if

def valid?(context = nil)
  context ||= default_validation_context
  output = super(context)
  errors.empty? && output
end