Правильная работа с файлами

# -*- coding: utf-8 -*-
import re
import codecs
import sys
from pprint import pprint
 
f_exclusions_name = 'words_posted2.txt' #file with words to exclude
f_exclusions_name2 = 'words_I_want_to_exclude_3.txt' #file with words I want to exclude
file_in_name = 'anki_out3.txt' #input file name
file_out_htm_name = 'out3.htm' #output html file name
file_out_txt_name = 'out3.txt'#output txt file name
word_to_exclude_next_time_file_name = 'words_posted3.txt'
 
html_head = u'''
<html>
 <head>
 <title>Words list 3</title>
 <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
 </head>
 <body>
'''
 
 
to_exclude_dict = {} #dict of words to exclude
excluded_words_dict = {} #dict of excluded words
word_to_exclude_next_time_dict = {}
 
#Forming to_exclude_dict dictionary
try:
    f_exclusions = codecs.open(f_exclusions_name,encoding='UTF-8')
except IOError:
    print('Can\'t open the file {0}'.format(f_exclusions_name))
    sys.exit(1)
else:
    for line in f_exclusions:
        line = line.rstrip('\n\r ')
        to_exclude_dict[line] = True
finally:
    f_exclusions.close()
 
try:
    f_exclusions = codecs.open(f_exclusions_name2,encoding='UTF-8')
except IOError:
    print('Can\'t open the file {0}'.format(f_exclusions_name2))
else:
    for line in f_exclusions:
        line = line.rstrip('\n\r ')
        to_exclude_dict[line] = True
finally:
    f_exclusions.close()
 
 
 
try:
    f_in = codecs.open(file_in_name,encoding='UTF-8')
except IOError:
    print('Can\'t open the file {0}'.format(file_in_name))
else:
    try:
        f_out_htm = codecs.open(file_out_htm_name,mode='w',encoding='UTF-8')
    except IOError:
        print('Can\'t open the file {0}'.format(file_out_htm_name))
    else:
        try:
            f_out_txt = codecs.open(file_out_txt_name,mode='w',encoding='UTF-8')
        except IOError:
            print('Can\'t open the file {0}'.format(file_out_txt_name))
        else:
            try:
                word_to_exclude_next_time_file = codecs.open(word_to_exclude_next_time_file_name,mode='w',encoding='UTF-8')
            except IOError:
                print('Can\'t open the file {0}'.format(word_to_exclude_next_time_file_name))
            else:
                f_out_htm.write(html_head)
                f_out_htm.write(u'<table border="1" cellspacing ="0" cellpadding ="3" width="100%">')
                f_out_htm.write(u'<tr>')
                f_out_htm.write(''.join((u'<th>',u'№',u'</th><th>',u'Слово',u'</th><th>',u'Значение',u'</th>')))
                f_out_htm.write(u'</tr>\n')
 
                pattern1 = re.compile(r'\t')
                pattern2 = re.compile(r'</?span.*?>|^ +| +$|\n')
                pattern3 = re.compile(r'<img src="(.*?)" />')
 
                i = 0
                for j, line in enumerate(f_in):
                    #print(u'Line in: {0}\n'.format(line))
 
                    strings = pattern1.split(line)
 
                    word = pattern2.sub('',strings[0]) #striped of html-garbage string[0]
 
                    word_to_exclude_next_time_file.write(word+u'\n')
                    #print(u'Word: {0}'.format(word))
 
 
                    #Adding the found values in the to_exclude_dict into the excluded_words_dict
                    if word in to_exclude_dict:
                        #print(u'Excluded: {0}\n'.format(word))
                        excluded_words_dict[word] = True
                        continue #no parsing for the data which is in the to_exclude_dict
 
                    f_out_txt.write(word+'\n')
 
                    f_out_htm.write(u'<tr>')
                    i += 1 #number of the table row
                    line = u'<td>'+'{0}'.format(i)+'</td><td>'+strings[0]+u'</td>'+u'<td>'
 
                    definition = strings[2]
                    image = pattern3.search(definition)
                    if image:
                        #print(u'Image detected: {0}'.format(image.group(0)))
                        #adding my public DropBox address
                        definition = pattern3.sub(u'<img style="border:5px solid white" src="http://dl.dropbox.com/u/7801003/Different.media/\g<1>" width="50%" />',strings[2])
                        #print(u'Replaced definition string: {0}\n'.format(definition))
 
                    if definition: #there may be no definition
                        line += definition
                    else:
                        line += '&nbsp' #otherwise the cells are empty and have no borders in the html
 
                    #Adding examples
                    if strings[3]: #there may be no examples
                        line += u'<p><span style="color:blue; font-style:italic;">'+strings[3]+u'</span></p>'
 
                    line += u'</td>'
 
                    f_out_htm.write(line)
                    f_out_htm.write(u'</tr>\n')
 
                f_out_htm.write(u'</table>')
            finally:
                word_to_exclude_next_time_file.close()
        finally:
            f_out_txt.close()
    finally:
        f_out_htm.close()
finally:
    f_in.close()
 
#the set of words which haven't been excluded for some reason
not_excluded = set(to_exclude_dict) - set(excluded_words_dict)
print(u'\nWords that haven\'t been excluded:'.format(word))
for word in not_excluded:
    print(u'{0}'.format(word))
 
print('\nParsing completed')

try:
    with codecs.open(file_in_name,encoding='UTF-8') as f_in,\
    codecs.open(file_out_htm_name,mode='w',encoding='UTF-8') as f_out_htm,\
    codecs.open(file_out_txt_name,mode='w',encoding='UTF-8') as f_out_txt,\
    codecs.open(word_to_exclude_next_time_file_name,mode='w',encoding='UTF-8') as word_to_exclude_next_time_file:
        processing()
except IOError as err:
    if err.filename == file_out_htm_name:
        # do something
    elif err.filename == file_in_name:
        # do something
    elif err.filename == file_out_txt_name:
        # do something
    elif err.filename == word_to_exclude_next_time_file_name:
        # do something
    else:
        print("Something is really wrong going here. Have a closer look on it!")