def connect(self): 
        try:
            self.connection = pymongo.Connection(self.host, self.port)
            self.db = self.connection[self.name]
        except AutoReconnect:
            raise DatabaseException("It's not possible connect to the database")
def gaussian(data, mean, covariance):
    """!
    @brief Calculates gaussian for dataset using specified mean (mathematical expectation) and variance or covariance in case
            multi-dimensional data.