'Determine if dictionary has item with specific key.
Args:
key: Key to check for presence.  Key is case insensitive, so
"d.has_key(\'Key\')" evaluates to the same value as "d.has_key(\'key\')".
Returns:
True if dictionary contains key, else False.'

def has_key(self, key):

    return (key.lower() in self.caseless_keys)
