code: def lock(self, filename):
      if filename in self.locks:
          self.locks[filename] += 1
          return True
      else:
          cmd = 'ln -s /dev/null "%s.lock" 2> /dev/null' % (filename)
          fail = os.system(cmd)
          if not fail:
              self.locks[filename] = 1
          return not fail
  
file_path: auptimizer/src/aup/Proposer/spearmint/Locker.py
imports: import os
  import sys
  import time
label_desc: Use image node_id 3 for calling the Locker obj's underlying member method code with example usage: obj.lock(filename) and returns: True, unknown