This constant is the only value for the type NoneType .
None is usually used to indicate that that there is no specific meaning.
For example, to designate a default parameter of a function.
# Can't assign a value
None = 10 # SyntaxError: can't assign to keyword
# Use as default parameter value.
def print_some (value = None):
# If no value is passed, use some.
value = value or 'some'
print (value)
print_some () # some
# Checks for None
# are done with is, not ==
if something is None:
pass
if something is not None:
pass