@abstractmethod<EOL><INDENT>def count(self, model, context):<DEDENT>
Returns the number of records that exist for this connection for
a given lookup and options.

:sa         distinct, select

:param      table_or_join | <orb.Table> || <orb.Join>
            lookup        | <orb.LookupOptions>
            options       | <orb.Context>

:return     <int>