Tuple (tuple)
Tuple is an immutable sequence, and its operation is basically the same as that of a list (that is, it cannot be modified)
. Tuple is used when the data is not changed, and the rest is
created with a list : ()
If the tuple is not empty Then there is at least one in the tuple, such as (the following example is a special case)
The usual situation is 
unpacking : assign each element in the tuple to each variable (the number of elements must be equal to the number of variables)
If not equal, then the number 
can be added in front of the variable to solve 
not added to the variable positions will tuple related elements correspond, but preceded by the variable will correspond to those extra elements (in the form of a list) , But there cannot be two