#  arbitrary numbers of arguments.

def add(*args):
	return sum(args)
    
print("""
def add(*args):
	return sum(args)
""")

#    *: args accept multiple arguments.
#       args <- (1,2,3,4,5)
#       sum(1,2,3,4,5) -> 15
print(f"add(1,2,3,4,5): {add(1,2,3,4,5)}")

print(f"add(10,2,3,4,5,6,7): {add(10,2,3,4,5,6,7)}")



def multiplied_sum(*numbers, multiplier=1):
    total_sum = sum(numbers)
    return total_sum * multiplier

print("""
def multiplied_sum(*numbers, multiplier=1):
    total_sum = sum(numbers)
    return total_sum * multiplier
""")
#   *: numbers <-- (1,2,3,4): 10
#   multiplier <- 5
print(f"multiplied_sum(1,2,3,4,multiplier=5): {multiplied_sum(1,2,3,4,multiplier=5)}")

#   *: numbers <-- (1,2,3,4,5): 15
#   multiplier <- 1 (default)
print(f"multiplied_sum(1,2,3,4,5): {multiplied_sum(1,2,3,4,5)}")


#   *: numbers <-- (1,2,3
#   multiplier <- 1
print(f"multiplied_sum(1,2,3): {multiplied_sum(1,2,3)}")

def multiplied_sum2(*numbers, multiplier):
    total_sum = sum(numbers)
    return total_sum * multiplier

print("""
def multiplied_sum2(*numbers, multiplier=1):
    total_sum = sum(numbers)
    return total_sum * multiplier
""")
#   *: numbers <-- (1,2,3,4): 10
#   multiplier <- 5
print(f"multiplied_sum2(1,2,3,4,multiplier=5): {multiplied_sum2(1,2,3,4,multiplier=5)}")

'''

Error: since multiplier have not default value, must submit a named argument.
#   *: numbers <-- (1,2,3,4,5): 15
#   multiplier <- 1 (default)
print(f"multiplied_sum2(1,2,3,4,5): {multiplied_sum2(1,2,3,4,5)}")


#   *: numbers <-- (1,2,3
#   multiplier <- 1
print(f"multiplied_sum2(1,2,3): {multiplied_sum2(1,2,3)}")
'''

def area(*, width, length):
    return width * length
print("""
def area(*, width, length):
    return width * length
""")
    
print(f"area(width=2,length=3): {area(width=2,length=3)}")
print(
"""
print(f"area(2,3): {area(2,3)}")
TypeError: area() takes 0 positional arguments but 2 were given
"""
)