Print Hello and a given name in the following way:

>>> def print_hello(name):
...     print('Hello ' + name)
...

Call the function as follows:

>>> print_hello('Ivan')
Hello Ivan

Some functions do not have arguments, or the arguments have default values. Give the function a default argument value as follows:

>>> def print_hello(name='Ivan'):
...     print('Hello ' + name)
...
>>> print_hello()
Hello Ivan

Usually, we want to return a value. Define a function, which doubles input values as follows:

>>> def double(number):
...     return 2 * number
...
>>> double(3)
6