Class `SortExpression` allows you to customize how your search results are sorted.

`SortExpression` is defined in the `google.appengine.api.search` module.

## Constructor

The constructor for class `SortExpression` is defined as follows:


class SortExpression(expression=None, direction=DESCENDING, default_value=None)

:
    Sort results by the specified scoring expression.

:

    Arguments

    expression

    :   An expression to be evaluated when sorting results for each matching document. The expression can simply be a field name, or some compound expression such as
        `_score + count(likes) * 0.1`
        which will add the score from a scorer to a count of the values of a
        `likes` field weighted by a factor of 0.1.

    direction

    :   The direction to sort the search results, either ASCENDING or DESCENDING.

    default_value

    :   The default value of the expression, if no field is present and cannot be calculated for a document. A text value must be specified for text sorts. A numeric value must be specified for numeric sorts.

    Result value

    :   A new instance of class `SortExpression`.

    Exceptions

    TypeError

    :   If any of the parameters have an invalid type, or an unknown attribute is passed.

    ValueError

    :   If any parameter has an invalid value.

    <br />

## Properties

An instance of class `SortExpression` has the following properties:

expression

:   Returns the expression used to sort matched results.

direction

:   Returns the direction of sort expression: `ASCENDING` or `DESCENDING`.

default_value

:   Returns a default value for the expression if no other value could be computed.