code: def find_one(self, filter=None, fields=None, skip=0, sort=None):
          
          result = self.find(filter=filter, fields=fields, skip=skip, limit=1, sort=sort)
          if len(result) > 0:
              return result[0]
          else:
              return None
docs: Similar to find. This method will only retrieve one row.
          If no row matches, returns None