What is the purpose of the '+=' operator in Python?

The purpose of the '+=' operator in Python is to serve as a reassignment operator that adds a specified value to a variable. When you use this operator, it takes the current value of the variable on the left side, adds the value on the right side, and then reassigns the result back to the variable. For instance, if you have a variable x with a value of 5 and then execute x += 3, x will now hold the value of 8. This operator simplifies the syntax for incrementing values and can be particularly useful in loops or cumulative calculations, allowing for more concise and readable code.

Understanding that the '+=' operator is both a reassignment and addition operator helps highlight its utility in modifying variable values effectively, which is a fundamental concept in Python programming.