old_contents: '''Search all our doc comments for "Example" blocks and try executing them.'''
  import re
  import sourcer
  
  
  def run_examples(package):
      pattern = re.compile(r'''
          (\s*)      # initial indent
          Example    # magic keyword
          ([^\n]*)   # optional description
          \:\:       # magic marker
  
          # Each line of the example is indented
          # by four additional spaces:
          (\n((\1\ \ \ \ .*)?\n)+)
          ''',
          re.IGNORECASE | re.VERBOSE
      )
  
      for k, v in package.__dict__.iteritems():
          if k.startswith('__') and k.endswith('__'):
              continue
          doc = getattr(v, '__doc__') or ''
          for m in pattern.finditer(doc):
              indent = '\n    ' + m.group(1)
              body = m.group(3)
              example = body.replace(indent, '\n')
              print '  Running', k, 'example', m.group(2).strip()
              exec example in {}
  
  
  if __name__ == '__main__':
      run_examples(sourcer)
  
new_contents: '''Search all our doc comments for "Example" blocks and try executing them.'''
  import re
  import sourcer.expressions
  
  
  def run_examples(package):
      pattern = re.compile(r'''
          (\s*)      # initial indent
          Example    # magic keyword
          ([^\n]*)   # optional description
          \:\:       # magic marker
  
          # Each line of the example is indented
          # by four additional spaces:
          (\n((\1\ \ \ \ .*)?\n)+)
          ''',
          re.IGNORECASE | re.VERBOSE
      )
  
      for k, v in package.__dict__.iteritems():
          if k.startswith('__') and k.endswith('__'):
              continue
          doc = getattr(v, '__doc__') or ''
          for m in pattern.finditer(doc):
              indent = '\n    ' + m.group(1)
              body = m.group(3)
              example = body.replace(indent, '\n')
              print '  Running', k, 'example', m.group(2).strip()
              exec example in {}
  
  
  if __name__ == '__main__':
      run_examples(sourcer.expressions)
  
subject: Test the doc comments in the expressions module.