f-Strings usage

>>> website = 'Quickref.ME'
>>> f"Hello, {website}"
"Hello, Quickref.ME"
>>> num = 10
>>> f'{num} + 10 = {num + 10}'
'10 + 10 = 20'
>>> f"""He said {"I'm John"}"""
"He said I'm John"
>>> f'5 {"{stars}"}'
'5 {stars}'
>>> f'{{5}} {"stars"}'
'{5} stars'
>>> name = 'Eric'
>>> age = 27
>>> f"""Hello!
...  I'm {name}.
...  I'm {age}."""
"Hello!\n I'm Eric.\n I'm 27."

it is available since Python 3.6, also see: Formatted string literals