[{'role': 'user', 'content': "Analyze the following clause from a privacy policy and determine if it's fair or unfair. Also identify any privacy practices mentioned: When transacting with another user, the other user may request and we may provide him/her with information about you necessary to complete the transaction, such as your name, account ID, email address, contact details, shipping and billing address, or other information from you needed to promote the reliability and security of the transaction. If a transaction is held, fails, or is later invalidated, we may also provide the other user with details of the unsuccessful transaction. The other user receiving your information is not allowed to use this information for purposes unrelated to the transaction, such as to contact you for marketing purposes, unless you have express consented to it. Contacting users with unwanted or threatening messages is a violation of our User Agreement."}, {'role': 'assistant', 'content': 'This clause is fair. The privacy practices mentioned are: nan.'}]