The reason for using a constant is to have a name and an explicitly defined type for
a value, rather than just writing the value as a literal. This makes the model more intelligible
to the reader, since the name and type convey much more information about the
intended use of the object than the literal value alone. Furthermore, if we need to change
the value as the model evolves, we only need to update the declaration. This is much easier
and more reliable than trying to find and update all instances of a literal value throughout
a model. It is good practice to use constants rather than writing literal values within a
model.