You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: canvas.rb
    path of file: ./repos/truffleruby/bench/chunky_png/chunky_png/lib/chunky_png
    
    the code of the file until where you have to start completion: require 'chunky_png/canvas/png_encoding'
require 'chunky_png/canvas/png_decoding'
require 'chunky_png/canvas/adam
    
    def assert_width!(vector_length)
      if width != vector_length
        raise ChunkyPNG::ExpectationFailed,
          "The length of the vector (#{vector_length}) does not match the canvas width (#{width})!"
      end
      true
    end