def read_attr(attr_name, to_call = nil)
      val = self[attr_name]
      val && to_call ? val.__send__(to_call) : val
    end
def read_attr(attr_name, to_call = nil)
      val = self[attr_name]
      val && to_call ? val.__send__(to_call) : val
    end
Helper method to read an attribute

 @param [#to_sym] attr_name the name of the attribute
 @param [String, Symbol, nil] to_call the name of the method to call on
 the returned value
 @return nil or the value