code: def cd(path, on=os):
      
      
      original = on.getcwd()
      on.chdir(path)
      
      yield
      
      on.chdir(original)
docs: Change the current working directory within this context.
      
      Preserves the previous working directory and can be applied to remote
      connections that offer @getcwd@ and @chdir@ methods using the @on@
      argument.