use .lower() in f string code example

Example 1: f string in python

# f-strings are short for formatted string like the following
# you can use the formatted string by two diffrent ways
# 1
name = "John Smith"
print(f"Hello, {name}")		# output = Hello, John Smith

# 2
name = "John Smith"
print("Hello, {}".format(name))		# output = Hello, John Smith

Example 2: python f string

>>> name = "Eric"
>>> age = 74
>>> f"Hello, {name}. You are {age}."
'Hello, Eric. You are 74.'