String istitle() Method | Python Tutorial

[Dizmore]

thanks for your tutorials! so i have a question, if i want to know that the input has only letters i.e i've done this as practice
"def birth_year():
while True:
z = input("What is your birthyear? :")
if z.isdigit(): there any kind of method like this but only for letters?}
z = int(z)
if MIN<=z<= MAX:
break
else:
print(f"The Birth year is invalid. It must be between {MIN} and {MAX}")
else:
print("Input a valid birthyear.")
return z