convert source code files to pdf format in python

 import os
 import sys
 
 def find_file(root_dir, type):
     dirs_pool = [root_dir]
     dest_pool = []
 
     def scan_dir(directory):
         entries = os.walk(directory)
         for root, dirs, files in entries:
             dirs_pool.extend([os.path.join(root, dir_entry) for dir_entry in dirs])
             for file_entry in files:
                 if type in str(file_entry)[-len(type):]:
                     dest_pool.append(''.join(os.path.join(root, file_entry)))
 
     while dirs_pool:
         scan_dir(dirs_pool.pop())
     return dest_pool
 
 def gen_ps(root_dir, type):
     vim_cmd = 'vim -me -e -c ":hardcopy >%.ps" -c ":q" '
     ps2pdf_cmd = 'ps2pdf {filename}.ps {filename}.pdf'
     dests = find_file(root_dir, type)
     if not dests:
         return
     print 'found these source code files:'
     for dest in dests:
         print dest
     print 'begin generate ps files!'
     for dest in dests:
         command = ''.join([vim_cmd, dest])
         print command
         os.system(command)
     for dest in dests:
         command = ps2pdf_cmd.format(filename=dest)
         print command
         os.system(command)
 
 if __name__ == '__main__':
     if len(sys.argv) == 3:
         gen_ps(sys.argv[1], sys.argv[2])
     else:
         print 'usage: python code2pdf.py directory filetype\n' \
               'such as: python code2pdf.py /home/bruce/python .py'