new_contents: #$ header function f(int, int [:])
  #$ header macro __g__(x) := f(x.shape, x)
  def f(n, a):
      for i in range(0, n):
          a[i] = i
  
  from numpy import zeros
  
  a = zeros(4, 'int')
  __g__(a)
  
  print('hello world')
  
subject: add test macro to codegen