Fixed errors found by linters

src/flake8/formatting/base.py

@@ -168,7 +168,7 @@ class BaseFormatter(object):
 
     def _write(self, output):
         """Handle logic of whether to use an output file or print()."""
-        if sys.version_info < (3, 0) and isinstance(output, unicode):
+        if sys.version_info < (3, 0) and not isinstance(output, str):
             output = output.encode('UTF-8')
         if self.output_fd is not None:
             self.output_fd.write(output + self.newline)

src/flake8/options/manager.py

@@ -268,7 +268,9 @@ class OptionManager(object):
             setattr(options, option.dest, option.normalize(old_value))
 
     def parse_args(self, args=None, values=None):
-        """Implement simple proxy to calling the OptionParser's parse_args method."""
+        """
+        Use simple proxy to calling the OptionParser's parse_args method.
+        """
         self.generate_epilog()
         self.update_version_string()
         options, xargs = self.parser.parse_args(args, values)