Module Attribute behaviour during compilation

Questions & Help Questions
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1

I am just doing some poking around with module attribute and I created the following code:

defmodule ModuleAttribute do
  Module.register_attribute(__MODULE__, :test_attribute, accumulate: true)
  @test_attribute 1
  @test_attribute 10
  def increase(), do: IO.inspect(@test_attribute, label: "Value")
  @test_attribute 20
end

When I run iex -S mix i get the following values

iex(40)> ModuleAttribute.increase     
Value: [10, 1]

If my understanding of elixir compilation is correct, should it be [1, 10, 20]? I am not sure why 20 didn’t get added in during compilation.