send.rb

class Person
 attr_accessor :name, :age, :weight

 def initialize(hash)
  hash.each do |key, value|
   setter_method = key.to_s + "="
   send(setter_method, value)
  end
 end
end

p = Person.new(name: 'Bob', age: 10, weight: 100)
p.name
# => Bob