Lab 7. Creating Equivalent Element Definitions

Modify the schema that you created in Lab 6.
warranty and guarantee are terms that are used
interchangeably in our culture (U.S.).  Thus,
our schema should reflect that by allowing the 
writer of an XML instance document to use the
term warranty or guarantee.  For this lab you
are to create an element quivalence definition
for the warranty element.  Then, modify juicers.xml
(from lab 1) such that sometimes warranty is used
and sometimes guarantee is used.  Validate the
new schema as well as the instance document.