Remove dep on six

Signed-off-by: Philippe Ombredanne <pombredanne@nexb.com>

Author: pombredanne

setup.cfg

@@ -16,6 +16,11 @@ classifiers =
     Intended Audience :: Developers
     Programming Language :: Python :: 3
     Programming Language :: Python :: 3 :: Only
+    Programming Language :: Python :: 3.6
+    Programming Language :: Python :: 3.7
+    Programming Language :: Python :: 3.8
+    Programming Language :: Python :: 3.9
+    Programming Language :: Python :: 3.10
     Topic :: Software Development
     Topic :: Utilities
 
@@ -49,7 +54,6 @@ install_requires =
     attrs
     packageurl-python
     requests
-    six
 
 
 [options.packages.find]

src/fetchcode/packagedcode_models.py

@@ -34,7 +34,6 @@
 import attr
 from packageurl import normalize_qualifiers
 from packageurl import PackageURL
-from six import string_types
 
 from fetchcode.commoncode_datautils import choices
 from fetchcode.commoncode_datautils import Boolean
@@ -89,7 +88,7 @@ def logger_debug(*args):
     logger.setLevel(logging.DEBUG)
 
     def logger_debug(*args):
-        return logger.debug(' '.join(isinstance(a, string_types) and a or repr(a) for a in args))
+        return logger.debug(' '.join(isinstance(a, str) and a or repr(a) for a in args))
 
 
 class BaseModel(object):