operation with unicode parameters.  SQLAlchemy now passes both
the statement as well as the bound parameters as unicode
objects, as PyMySQL generally uses string interpolation
internally to produce the final statement, and in the case of
executemany does the "encode" step only on the final statement.
fixes #3337

as up-to-date recommendations as possible

and Pymysql under Python 2.   This refers to the SQL statements
themselves, not the parameters, and affects issues such as table
and column names using non-ASCII characters.   These drivers both
appear to support Python 2 Unicode objects without issue in modern
versions.
fixes #3121

sqlalchemy/orm, sqlalchemy/event, sqlalchemy/testing

to get all flake8 passing

pymysql) from working in Py3K, where a check for "connection
charset" would fail due to Py3K's more strict value comparison
rules.  The call in question  wasn't taking the database
version into account in any case as the server version was
still None at that point, so the method overall has been
simplified to rely upon connection.character_set_name().
[ticket:2933]