+if hasattr(shutil, 'get_terminal_size'):  # Python >= 3.3
+    compat_get_terminal_size = shutil.get_terminal_size
+else:
+    _terminal_size = collections.namedtuple('terminal_size', ['columns', 'lines'])
+
+    def compat_get_terminal_size(fallback=(80, 24)):
+        columns = compat_getenv('COLUMNS')
+        if columns:
+            columns = int(columns)
+        else:
+            columns = None
+        lines = compat_getenv('LINES')
+        if lines:
+            lines = int(lines)
+        else:
+            lines = None
+
+        if columns is None or lines is None or columns <= 0 or lines <= 0:
+            try:
+                sp = subprocess.Popen(
+                    ['stty', 'size'],
+                    stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+                out, err = sp.communicate()
+                _lines, _columns = map(int, out.split())
+            except Exception:
+                _columns, _lines = _terminal_size(*fallback)
+
+            if columns is None or columns <= 0:
+                columns = _columns
+            if lines is None or lines <= 0:
+                lines = _lines
+        return _terminal_size(columns, lines)
+
+try:
+    itertools.count(start=0, step=1)
+    compat_itertools_count = itertools.count
+except TypeError:  # Python 2.6
+    def compat_itertools_count(start=0, step=1):
+        n = start
+        while True:
+            yield n
+            n += step
+
+if sys.version_info >= (3, 0):
+    from tokenize import tokenize as compat_tokenize_tokenize
+else:
+    from tokenize import generate_tokens as compat_tokenize_tokenize