code: def ParseDepends(self, filename, must_exist=None, only_one=0):
          filename = self.subst(filename)
          try:
              fp = open(filename, 'r')
          except IOError:
              if must_exist:
                  raise
              return
          lines = SCons.Util.LogicalLines(fp).readlines()
          lines = [l for l in lines if l[0] != '
          tdlist = []
          for line in lines:
              try:
                  target, depends = line.split(':', 1)
              except (AttributeError, ValueError):
                  pass
              else:
                  tdlist.append((target.split(), depends.split()))
          if only_one:
              targets = []
              for td in tdlist:
                  targets.extend(td[0])
              if len(targets) > 1:
                  raise SCons.Errors.UserError(
                              "More than one dependency target found in `%s':  %s"
                                              % (filename, targets))
          for target, depends in tdlist:
              self.Depends(target, depends)