Functions, Methods, and Operators Terminology on Python
On Python, The term function is used to refer to a subroutine that can be executed independently, and the term method is used to refer to a function that can only be executed when bound to an object, that is, called on an instance of a particular class.
An operator may be independent or it may be bound to an object, but unlike functions and methods, operators do not use parentheses. Operators that are represented by symbols such as +, *, and < are rather obviously called operators, but operators that have names such as del and print are often called statements.
Python functions do not have to be pure in the mathematical sense: They do not have to return a value and they can modify their arguments. Python functions are like C and C++ functions, or like Pascal functions that take var parameters. Python methods are like C++ or Java member functions.