Fix Python 2.7 supporting

CHANGELOG.md

@@ -1,3 +1,8 @@
+0.0.19 (2019-04-06)
+===================
+  * Fix Python 2.7 supporting
+
+
 0.0.18 (2019-04-06)
 ===================
   * Added supporting Django 2.2

transtool/__init__.py

@@ -1,3 +1,3 @@
-__version__ = '0.0.18'
+__version__ = '0.0.19'
 
 default_app_config = 'transtool.apps.TrantoolConfig'

transtool/tools.py

@@ -1,15 +1,22 @@
-from datetime import datetime
+import sys
 import difflib
 import os
 import re
 import polib
+from datetime import datetime
 from django.utils.encoding import force_str
 from django.utils import timezone
 
 
 lc_dir_re = re.compile(r'^.*?locale/[\w\-]{2,5}/LC_MESSAGES$')
 
 
+def list_clear(list_obj):
+    if sys.version_info >= (3, 5):
+        list_obj.clear()
+    del list_obj[:]
+
+
 def get_lc_files_list(search_root, exts=('.po', '.mo')):
     """
     Returns list of tuple (absolute path, relative path)
@@ -29,10 +36,10 @@ def get_diff_po(po1_fn, po2_fn):
     po1_lines = []
     po2_lines = []
     for entry in sorted(polib.pofile(po1_fn, wrapwidth=8000), key=lambda obj: obj.msgid):
-        entry.occurrences.clear()
+        list_clear(entry.occurrences)
         po1_lines.append(force_str(entry))
     for entry in sorted(polib.pofile(po2_fn, wrapwidth=8000), key=lambda obj: obj.msgid):
-        entry.occurrences.clear()
+        list_clear(entry.occurrences)
         po2_lines.append(force_str(entry))
     added = removed = 0
     for diff_line in difflib.unified_diff(po1_lines, po2_lines):