"""
Exercise 3.20 from "A primer on ..."
Define the functions hw1-hw3 so that the function
listed function calls work and give the specified output.
"""

def hw1():
    return "Hello, world!"

def hw2():
    print("Hello, world!")


def hw3(str1, str2):
    return str1 + str2

"""
The function calls below were given in the
question text, with specified output in comments:
"""

print(hw1())
#Hello, World!

hw2()
#Hello, World!

print(hw3('Hello, ', 'World!'))
#Hello, World!

print(hw3('Python ', 'function'))
#Python function


"""
Terminal> python hw_func.py 
Hello, world!
Hello, world!
Hello, World!
Python function
"""