Removing validation of a model declared on a gem

model_extension.rb

# We have to remove validations on email, as it's no longer needed.
# Based on a solution found at http://stackoverflow.com/questions/7545938/how-to-remove-validation-using-instance-eval-clause-in-rails
Model.class_eval do
  _validators.reject!{ |key, _| key == :field }


  _validate_callbacks.each do |callback|
    callback.raw_filter.attributes.delete :field
  end

  _validate_callbacks.reject! do |callback|
    callback.raw_filter.attributes.empty? || callback.raw_filter.attributes == [:field]
  end

end

model_extension_rails_4.rb

# We have to remove validations on email, as it's no longer needed.
# Based on a solution found at http://stackoverflow.com/questions/7545938/how-to-remove-validation-using-instance-eval-clause-in-rails
Model.class_eval do
  _validators.delete(:template)

  _validate_callbacks.each do |callback|
    if callback.raw_filter.respond_to? :attributes
      callback.raw_filter.attributes.delete :template
    end
  end
end