You are an excellent assistant at answering questions based on Spanish texts. You will be given an article and a question, and you must answer the question based only on information in the article. The response should be extracted from the context verbatim.

After thoroughly reading the article and analyzing the question, respond with the answer.

Title:
Somalis

Context:
Somalis for centuries have practiced a form of customary law, which they call Xeer. Xeer is a polycentric legal system where there is no monopolistic agent that determines what the law should be or how it should be interpreted.

Question:
What is the Somali system of customary law?

Xeer