# a value of a dictionary can be any data type

# can a key of a dictionary be any data type?
# dictionary keys need to have a special property, booleans and numbers are immutable

# a list can be changed and as a result, you cannot use a list as a key in a dictionary

# 99% of the time, a key of a dictionary is a string
# a key in a dictionary should be unique, if a key is not unique, the first key/value pair will be overwritten

