The places inspect.getargspec was being used were causing problems for
newer Python versions.

unambiguous tracking of all object lifecycle state transitions
in terms of the :class:`.Session` itself, e.g. pending,
transient,  persistent, detached.   The state of the object
within each event is also defined.
fixes #2677
- Added a new session lifecycle state :term:`deleted`.  This new state
represents an object that has been deleted from the :term:`persistent`
state and will move to the :term:`detached` state once the transaction
is committed.  This resolves the long-standing issue that objects
which were deleted existed in a gray area between persistent and
detached.   The :attr:`.InstanceState.persistent` accessor will
**no longer** report on a deleted object as persistent; the
:attr:`.InstanceState.deleted` accessor will instead be True for
these objects, until they become detached.
- The :paramref:`.Session.weak_identity_map` parameter is deprecated.
See the new recipe at :ref:`session_referencing_behavior` for
an event-based approach to maintaining strong identity map behavior.
references #3517

attached to session X" would fail to prevent the object from
also being attached to the new session, in the case that execution
continued after the error raise occurred.
fixes #3301

to :meth:`.Session.close`, except also calls
:meth:`.Connection.invalidate`
on all connections, guaranteeing that they will not be returned to
the connection pool.  This is useful in situations e.g. dealing
with gevent timeouts when it is not safe to use the connection further,
even for rollbacks.
references #3258

the given object if the object had been subject to a delete
operation that was flushed, but not committed.  This would also
affect related operations like :func:`.make_transient`.
fixes #3139

"binds" (e.g. engines to use), such engines can be associated with
mixin classes, concrete subclasses, as well as a wider variety
of table metadata such as joined inheritance tables.
fixes #3035

N occurrences of a parameterized string.   This allows parameterized
warnings that can refer to their arguments to be delivered a fixed
number of times until allowing Python warning filters to squelch them,
and prevents memory from growing unbounded within Python's
warning registries.
fixes #3178