Python is a powerful programming language that allows you to define and use procedures. Procedures, also known as functions, are a set of instructions that perform a specific task. They help to organize and modularize code, making it easier to understand and maintain.

In Python, procedures can be defined using the def keyword followed by the procedure name, parentheses, and a colon. The code block that makes up the procedure is indented below the definition.

Here is an example of a simple procedure in Python:

def greet():
    print("Hello, world!")

To call or execute a procedure, you simply use its name followed by parentheses. If the procedure requires any arguments, you can pass them inside the parentheses.

For example, to call the greet procedure defined above, you would write:

greet()

Procedures can also accept parameters, which are values passed into the procedure when it is called. These parameters are defined inside the parentheses when defining the procedure.

Here is an example of a procedure that accepts a parameter:

def double(number):
    result = number * 2
    print(result)

You can call the double procedure and pass a value for the number parameter:

double(5)

Procedures can also return values using the return statement. This allows you to use the result of a procedure in other parts of your program.

Here is an example of a function that returns a value:

def add(a, b):
    result = a + b
    return result

You can call the add function and store the returned value in a variable:

sum = add(3, 4)