A platform for verifying the validity of changes to dynamic data modifiable during the runtime execution of an agent. The subject invention also involves pharmaceutical compositions containing such compounds, and methods for treating or preventing diseases or disorders using such compounds. The stacker includes an improved sheet feed mechanism that enables sheets having different characteristics to be fed without disassembling any portion of the mechanism or the stacker. A space is defined between an outer surface of the motor and an interior surface of the motor housing.