code: def delta_encode(nums):
      base = 0
      for n in nums:
          yield n - base
          base = n
  
imports: from array import array
  from whoosh.compat import xrange
  from whoosh.system import emptybytes
  from whoosh.system import pack_byte, unpack_byte
  from whoosh.system import pack_ushort_le, unpack_ushort_le
  from whoosh.system import pack_uint_le, unpack_uint_le
label_desc: Use image node_id 1 for calling a global function with example usage: delta_encode(nums) without return types