python - How to specify Type Hint for Parameters for Custom Classes? -


this question has answer here:

let's have created class defined below, , have called methods on it:

class student:      def __init__(self, name):         self.name = name         self.friends = []      def add_friend(self, new_friend: student):         self.friends.append(new_friend)  student1 = student("brian") student2 = student("kate") student1.add_friend(student2)

the method add_friend has parameter called new_friend, student object. how use type hints specify that? assumed have enter name of class, new_friend: student not work. when run it, nameerror: name 'student' not defined. tried new_friend: __main__.student, gives me same error. doing wrong?

per pep-484, use string name of class forward references:

class student:      def __init__(self, name):         self.name = name         self.friends = []      def add_friend(self, new_friend: 'student'):         self.friends.append(new_friend)

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