Step is a of with functions and example object that represents a single time step without and conventions.
All Step objects are and as such can be automatically generated from appropriately formatted text prefixed with the symbol %
The text must be of the form: %xU, where x is some integer and U is the unit identifier in the form of one of the letters described in
Note case and spaces are ignored.
For example: %2M represents a two month interval.
Note that a value like %1B involving business days makes little sense on its own because of the absence of a calendar definition.
But it could make sense in a wider context where a calendar is defined elsewhere.