class Example
  def initialize
     @private_data =  
  end
  private
  def hidden_method
     
  end
end
example = Example.new
p example.private_methods(false) 

p example.send(:hidden_method) 
p example.instance_variables 
p example.instance_variable_get:@private_data 
p example.instance_variable_set:@private_data, 42 
p example.instance_variable_get:@private_data