```
my_array = [[1, 'foo_parent', nil], [2,'bar_is_son_of_foo', 1], [3, 'zok_is_son_of_bar', 2]]

def children_block
  Proc.new do |c|  
    if c.is_a? Array
      c[2] == self[0] 
    end
  end
end

my_array.send(:select) &children_block

```

gives me ArgumentError: wrong number of arguments (0 for 1..4)