kind_of?

■ ri

 -------------------------------------------------------- Object#kind_of?
      obj.is_a?(class)       => true or false
      obj.kind_of?(class)    => true or false
 ------------------------------------------------------------------------
      Returns  true  if _class_ is the class of _obj_, or if _class_ is
      one of the superclasses of _obj_ or modules included in _obj_.
 
         module M