class Foo(object):  def bar(self):    print 'Foo.bar'def bar(self):  print 'Modified bar'Foo().bar()Foo.bar = barFoo().bar()

from eventlet import patcher# *NOTE: there might be some funny business with the "SOCKS" module# if it even still existsfrom eventlet.green import socketpatcher.inject('ftplib', globals(), ('socket', socket))del patcherinject函數會將eventlet的socket模塊注入標準的ftplib中，globals dict被傳入以做適當的修改。讓我們接著來看一下inject的實現。__exclude = set(('__builtins__', '__file__', '__name__'))def inject(module_name, new_globals, *additional_modules):  """Base method for "injecting" greened modules into an imported module. It  imports the module specified in *module_name*, arranging things so  that the already-imported modules in *additional_modules* are used when  *module_name* makes its imports.  *new_globals* is either None or a globals dictionary that gets populated  with the contents of the *module_name* module. This is useful when creating  a "green" version of some other module.  *additional_modules* should be a collection of two-element tuples, of the  form (, ). If it's not specified, a default selection of  name/module pairs is used, which should cover all use cases but may be  slower because there are inevitably redundant or unnecessary imports.  """  if not additional_modules:    # supply some defaults    additional_modules = (      _green_os_modules() +      _green_select_modules() +      _green_socket_modules() +      _green_thread_modules() +      _green_time_modules())  ## Put the specified modules in sys.modules for the duration of the import  saved = {}  for name, mod in additional_modules:    saved[name] = sys.modules.get(name, None)    sys.modules[name] = mod  ## Remove the old module from sys.modules and reimport it while  ## the specified modules are in place  old_module = sys.modules.pop(module_name, None)  try:    module = __import__(module_name, {}, {}, module_name.split('.')[:-1])    if new_globals is not None:      ## Update the given globals dictionary with everything from this new module      for name in dir(module):        if name not in __exclude:          new_globals[name] = getattr(module, name)    ## Keep a reference to the new module to prevent it from dying    sys.modules['__patched_module_' + module_name] = module  finally:    ## Put the original module back    if old_module is not None:      sys.modules[module_name] = old_module    elif module_name in sys.modules:      del sys.modules[module_name]    ## Put all the saved modules back    for name, mod in additional_modules:      if saved[name] is not None:        sys.modules[name] = saved[name]      else:        del sys.modules[name]  return module

if new_globals is not None:  ## Update the given globals dictionary with everything from this new module  for name in dir(module):    if name not in __exclude:      new_globals[name] = getattr(module, name)