old_contents: #!/usr/bin/env python
  # -*- coding: utf-8 -*-
  
  '''@package _cookbook
  Python Cookbook
  
    - unittest
    - doctest
    - Number Division
    - Loop Techniques
    - Unpack Iterable
    - Output Format
    - Function Arguments
    - OOP
    - Context Manager
    - file I/O
    - Find & Sort Algorithms
    - Text Pattern
    - Network
    
  
  Python Command Line Options:
  
      `-t`  Issue a warning when a source file mixes tabs and spaces for
            indentation in a way that makes it depend on the worth of a tab
            expressed in spaces.
          
      `-tt` Issue a error when a source file mixes tabs and spaces for
            indentation in a way that makes it depend on the worth of a tab
            expressed in spaces.
          
      `-O`  Turn on basic optimizations. This changes the file name extension for
            compiled (bytecode) files from <em>.pyc</em> to <em>.pyo</em>, and set
            the <code>__debug__</code> to <code>False</code>.
         
      `-OO` Discard docstrings in addition to the <em>-O</em> optimizations.
  
        
  Copyright (c) 2014 Li Yun <leven.cn@gmail.com>
  All Rights Reserved.
  
  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
  LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  POSSIBILITY OF SUCH DAMAGE.
  '''
  
  from __future__ import print_function
  
  
  if __name__ == '__main__':
      print('Hello Python!')
new_contents: #!/usr/bin/env python
  # -*- coding: utf-8 -*-
  
  '''@package _cookbook
  Python Cookbook
  
    - unittest
    - doctest
    - Number Division
    - Loop Techniques
    - Unpack Iterable
    - Output Format
    - Function Arguments
    - OOP
    - Context Manager
    - file I/O
    - Find & Sort Algorithms
    - Text Pattern
    - Network
    
  
  ## Command Line Options
  
      `-t`  Issue a warning when a source file mixes tabs and spaces for
            indentation in a way that makes it depend on the worth of a tab
            expressed in spaces.
          
      `-tt` Issue a error when a source file mixes tabs and spaces for
            indentation in a way that makes it depend on the worth of a tab
            expressed in spaces.
          
      `-O`  Turn on basic optimizations. This changes the file name extension for
            compiled (bytecode) files from <em>.pyc</em> to <em>.pyo</em>, and set
            the <code>__debug__</code> to <code>False</code>.
         
      `-OO` Discard docstrings in addition to the <em>-O</em> optimizations.
      
  
  ## PEP
  
  - [PEP 8 - Style Guide for Python Code](http://legacy.python.org/dev/peps/pep-0008/)
  
  
        
  Copyright (c) 2014 Li Yun <leven.cn@gmail.com>
  All Rights Reserved.
  
  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
  LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  POSSIBILITY OF SUCH DAMAGE.
  '''
  
  from __future__ import print_function
  
  
  if __name__ == '__main__':
      print('Hello Python!')
  
subject: Add "PEP" into cookbook