"""Return an instance of the object based on the
- given identifier, or None if not found.
- The `ident` argument is a scalar or tuple of primary key column values
- in the order of the table def's primary key columns.
+ given identifier, or ``None`` if not found.
+ The ``ident`` argument is a scalar or tuple of
+ primary key column values
+ in the order of the mapper's "primary key" setting, which
+ defaults to the list of primary key columns for the
+ mapped :class:`.Table`.
+ :meth:`get` returns only a single mapped instance, or
+ ``None``. It is not intended to return rows or scalar
+ column values, therefore the :class:`.Query` must be
+ constructed only against a single mapper or mapped class,
+ not a SQL expression or multiple entities.
+ Other usages raise an error, or in the case of a single
+ column a deprecation warning is raised as of 0.6.8.