code: def load_parent(self, location):
          
          assert isinstance(location, basestring)
          found = b2.util.path.glob_in_parents(
              location, self.JAMROOT + self.JAMFILE)
  
          if not found:
              print "error: Could not find parent for project at '%s'" % location
              print "error: Did not find Jamfile.jam or Jamroot.jam in any parent directory."
              sys.exit(1)
  
          return self.load(os.path.dirname(found[0]))
docs: Loads parent of Jamfile at 'location'.
          Issues an error if nothing is found.