new_contents: from invoke import run, task
  import os
  
  @task
  def lint():
      for src in os.listdir("pystorm"):
          if src.endswith(".py"):
              run("pyflakes pystorm/{}".format(src))
              #run("pep8 pystorm/{}".format(src))
  
  @task
  def build(docs=False):
      run("python setup.py build")
      if docs:
          run("sphinx-build doc/source doc/_build")
  
  @task
  def develop():
      run("python setup.py develop")
  
subject: add an invoke builder for project development