Use identity operator is when comparing to None

Author: johnthagen

src/bootstrap/bootstrap.py

@@ -498,7 +498,7 @@ def get_toml(self, key):
 
         If the key does not exists, the result is None:
 
-        >>> rb.get_toml("key3") == None
+        >>> rb.get_toml("key3") is None
         True
         """
         for line in self.config_toml.splitlines():