code: def _make_boundary(text=None):
      # Craft a random boundary.  If text is given, ensure that the chosen
      # boundary doesn't appear in the text.
      token = random.randrange(sys.maxint)
      boundary = ("=" * 15) + (_fmt % token) + "=="
      if text is None:
          return boundary
      b = boundary
      counter = 0
      while True:
          cre = re.compile(
              "^--" + re.escape(b) + "(--)?$", re.MULTILINE
          )
          if not cre.search(text):
              break
          b = boundary + "." + str(counter)
          counter += 1
      return b
  
imports: import re
  import sys
  import time
  import random
  import warnings
  from cStringIO import StringIO
  from email.header import Header
label_desc: Use image node_id 2 for calling a global function with example usage: _make_boundary(text) and returns: b, boundary