UML class operations - urgent question

hello. can somebody help me with this problem, i dont know why there is a addCustomer() funtion in a Customer class.
Why should a new Customer object be created in a Customer object?

the example is as follows

Class Customer



How do you know that is what it’s doing? With only the information given, we have little clue on what that operation does and whether a new Customer is instantiated at all.

This isn’t really a UML question per se, since it is more in the genre of OO best practices.
However, I would personally think that addCustomer should not be in a class Customer. The method would make sense if it was located in a class CustomerList, or if the method was called createCustomer.