'Removes an `Expression` from the search domain. For more
information, see `Configuring Expressions`_ in the Amazon
CloudSearch Developer Guide .
:type domain_name: string
:param domain_name: A string that represents the name of a domain.
Domain names are unique across the domains owned by an account
within an AWS region. Domain names start with a letter or number
and can contain the following characters: a-z (lowercase), 0-9, and
- (hyphen).
:type expression_name: string
:param expression_name: The name of the `Expression` to delete.'

def delete_expression(self, domain_name, expression_name):

    params = {'DomainName': domain_name, 'ExpressionName': expression_name}
    return self._make_request(action='DeleteExpression', verb='POST', path='/', params=params)
