emptyDictionary = {}
print emptyDictionary
grades = { "A": 87, "B": 76, "C": 92, "D": 89 }
print "\nAll grades:", grades
print grades[ "A" ]
grades[ "A" ] = 90
print "A's new grade:", grades[ "A" ]
# add to an existing dictionary
grades[ "B" ] = 93
print "\nDictionary grades after modification:"
print grades
# delete entry from dictionary
del grades[ "C" ]
print "\nDictionary grades after deletion:"
print grades