Py3: Use six.string_types instead of basestring

pathod/language/base.py

@@ -3,6 +3,7 @@ import os
 import abc
 import pyparsing as pp
 
+import six
 from six.moves import reduce
 from netlib.utils import escaped_str_to_bytes, bytes_to_escaped_str
 from netlib import human
@@ -341,7 +342,7 @@ class OptionsOrValue(_Component):
         # it to be canonical. The user can specify a different case by using a
         # string value literal.
         self.option_used = False
-        if isinstance(value, basestring):
+        if isinstance(value, six.string_types):
             for i in self.options:
                 # Find the exact option value in a case-insensitive way
                 if i.lower() == value.lower():