code: def periodic_bc(f):
      nx, ny, ns = f.shape
  
      for j in range(ny):
          for k in range(ns):
              f[0, j, k] = f[nx - 2, j, k]
              f[nx - 1, j, k] = f[1, j, k]
      for i in range(nx):
          for k in range(ns):
              f[i, 0, k] = f[i, ny - 2, k]
              f[i, ny - 1, k] = f[i, 1, k]
  
file_path: pythran/pythran/tests/cases/d2q9_nxnyns.py
imports: import numpy
label_desc: Use image node_id 6 for calling a global function with example usage: periodic_bc(f) without return types