Similar to find. This method will only retrieve one row.
        If no row matches, returns None

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