code: def allocate(n):
      try:
          import mmap
  
          return mmap.mmap(-1, n)
      except (ImportError, OSError):
          try:
              from numpy import zeros
  
              return zeros(n, "B")
          except ImportError:
              from array import array
  
              return array("B", [0]) * n
  
imports: from mpi4py import MPI
label_desc: Use image node_id 3 for calling a global function with example usage: allocate(n) and returns: mmap, zeros, unknown