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

+forename
+lastname

addCustomer()

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.