old_contents: import os
  
  from ctasks \
      import \
          ccompile_task
  from task_manager \
      import \
          extension
  from task \
      import \
          Task
  from compiled_fun \
      import \
          compile_fun
  from utils \
      import \
          ensure_dir
  
  @extension(".f")
  def fortran_task(self, node):
      base = os.path.splitext(node)[0]
      # XXX: hack to avoid creating build/build/... when source is
      # generated. Dealing with this most likely requires a node concept
      if not base.startswith(self.env["BLDDIR"]):
          target = os.path.join(self.env["BLDDIR"], base + ".o")
      else:
          target = base + ".o"
      ensure_dir(target)
      task = Task("f77", inputs=node, outputs=target)
      task.env_vars = ["F77", "F77FLAGS"]
      task.env = self.env
      task.func = compile_fun("f77", "${F77} -c ${SRC} -o ${TGT[0]}",
                              False)[0]
      self.object_tasks.append(task)
      return [task]
  
  
new_contents: import os
  
  from task_manager \
      import \
          extension
  from task \
      import \
          Task
  from compiled_fun \
      import \
          compile_fun
  from utils \
      import \
          ensure_dir
  
  @extension(".f")
  def fortran_task(self, node):
      base = os.path.splitext(node)[0]
      # XXX: hack to avoid creating build/build/... when source is
      # generated. Dealing with this most likely requires a node concept
      if not base.startswith(self.env["BLDDIR"]):
          target = os.path.join(self.env["BLDDIR"], base + ".o")
      else:
          target = base + ".o"
      ensure_dir(target)
      task = Task("f77", inputs=node, outputs=target)
      task.env_vars = ["F77", "F77FLAGS"]
      task.env = self.env
      task.func = compile_fun("f77", "${F77} -c ${SRC} -o ${TGT[0]}",
                              False)[0]
      self.object_tasks.append(task)
      return [task]
  
subject: remove unused import.