Functions Worksheet
We’re writing functions now, so be mindful of the need for function calls. If you run a program that defines a function and doesn’t call it, you won’t get any output!
The tests always include a function call (which is how we test your definition).
Problem 1
Write a function hello_world that prints hello world! when called.
def test():
  """
  >>> hello_world()
  hello world!
  """
import doctest
doctest.testmod()Problem 2
Write a function multi_line that prints:
print
on
several
lineswhen called.
def multi_line():
  returnimport doctest
def test():
  """
  >>> multi_line()
  print
  on
  several
  lines
  """
  return
doctest.testmod()Problem 3
Write a function one that prints output from function one.
Write a second function, two that calls function one twice.
def ok():
  okk()
def okk():
  print(123)import doctest
def test():
  """
  >>> one()
  output from function one
  >>> two()
  output from function one
  output from function one
  """
  return
doctest.testmod()Problem 4
Write a function four that takes an integer argument and prints out the argument multiplied by 4.
def four(x):
  # your code hereimport doctest
def test():
  """
  >>> four(1)
  4
  >>> four(3)
  12
  >>> print(four(1)) # will fail if returning instead of printing
  4
  None
  """
  return
doctest.testmod()Problem 5
Write a function return_four that takes an integer argument and returns the argument multiplied by 4.
def return_four(x):
  # your code hereassert return_four(2) == 8
assert return_four(3) == 12Problem 6
Write a function repeater that takes a positive integer argument and “repeats” the integer, returning in a new int:
- repeater(5)returns int- 55
- repeater(10)returns int- 1010
- repeater(200)returns int- 200200
You’ll need to use the int and str functions to convert between int and string.
def repeater(z):
  # your code hereassert repeater(2) == 22
assert repeater(12) == 1212
assert repeater(0) == 00
assert repeater(150) == 150150