Migrate to python3

aeat.py

@@ -229,7 +229,7 @@ def remove_accents(unicode_string):
     unicode_string_nfd = ''.join(
         (c for c in unicodedata.normalize('NFD', unicode_string)
             if (unicodedata.category(c) != 'Mn'
-                or c in ('\u0327', '\u0303'))  # ç or ñ
+                or c in ('\\u0327', '\\u0303'))  # ç or ñ
             ))
     # It converts nfd to nfc to allow unicode.decode()
     return unicodedata.normalize('NFC', unicode_string_nfd)

aeat_mapping.py

@@ -58,7 +58,7 @@ class BaseTrytonInvoiceMapper(Model):
         for tax in taxes:
             base = tax.company_base
             parent = tax.tax.parent if tax.tax.parent else tax.tax
-            if parent.id in taxes_used.keys() and base == taxes_used[parent.id]:
+            if parent.id in list(taxes_used.keys()) and base == taxes_used[parent.id]:
                 continue
             total += (base + tax.company_amount)
             taxes_used[parent.id] = base

setup.py

@@ -95,10 +95,10 @@ setup(name='%s_%s' % (PREFIX, MODULE),
         'Natural Language :: Russian',
         'Natural Language :: Spanish',
         'Operating System :: OS Independent',
-        'Programming Language :: Python :: 2.7',
         'Programming Language :: Python :: 3.4',
         'Programming Language :: Python :: 3.5',
         'Programming Language :: Python :: 3.6',
+        'Programming Language :: Python :: 3.7',
         'Programming Language :: Python :: Implementation :: CPython',
         'Programming Language :: Python :: Implementation :: PyPy',
         'Topic :: Office/Business',
@@ -114,8 +114,4 @@ setup(name='%s_%s' % (PREFIX, MODULE),
     test_suite='tests',
     test_loader='trytond.test_loader:Loader',
     tests_require=tests_require,
-    use_2to3=True,
-    convert_2to3_doctests=[
-        'tests/scenario_aeat_sii.rst',
-        ],
     )