>>> import re
>>> m = re.search('(?<=abc)def', 'abcdef')
>>> m.group(0)
'def'

def abs(n):
  '''
  Function to get absolute value of number.

  Example:

  >>> abs(1)
  1
  >>> abs(-1)
  1
  >>> abs(0)
  0
  '''
  return n if n >= 0 else (-n)

class Dict(dict):
  '''
  Simple dict but also support access as x.y style.

  >>> d1 = Dict()
  >>> d1['x'] = 100
  >>> d1.x
  100
  >>> d1.y = 200
  >>> d1['y']
  200
  >>> d2 = Dict(a=1, b=2, c='3')
  >>> d2.c
  '3'
  >>> d2['empty']
  Traceback (most recent call last):
    ...
  KeyError: 'empty'
  >>> d2.empty
  Traceback (most recent call last):
    ...
  AttributeError: 'Dict' object has no attribute 'empty'
  '''
  def __init__(self, **kw):
    super(Dict, self).__init__(**kw)

  def __getattr__(self, key):
    try:
      return self[key]
    except KeyError:
      raise AttributeError(r"'Dict' object has no attribute '%s'" % key)

  def __setattr__(self, key, value):
    self[key] = value

if __name__=='__main__':
  import doctest
  doctest.testmod()

$ python mydict.py

$ python mydict.py
**********************************************************************
File "mydict.py", line 7, in __main__.Dict
Failed example:
  d1.x
Exception raised:
  Traceback (most recent call last):
   ...
  AttributeError: 'Dict' object has no attribute 'x'
**********************************************************************
File "mydict.py", line 13, in __main__.Dict
Failed example:
  d2.c
Exception raised:
  Traceback (most recent call last):
   ... 
  AttributeError: 'Dict' object has no attribute 'c'
**********************************************************************