IsTeamMember method for Dynamics CRM .Net developers

Crm.IsTeamMember.cs

public static bool IsTeamMember(IOrganizationService service, Guid userId, Guid teamId)
{
    var request = new RetrieveTeamsSystemUserRequest 
        { 
            EntityId = userId, 
            ColumnSet = new ColumnSet() 
        };

    var response = (RetrieveTeamsSystemUserResponse)service.Execute(request);

    return response.EntityCollection.Entities.Any(entity => entity.Id == teamId);
}