Why snake in my dream

Date: 7/1/2019

I always (may be twice in a month) seeing snake in my dream.. Sometimes it is in my room or near to my house or in yard and it will be cobra or python or other black snakes.. it is not bite me or my family but when it coming or seeing it I scared in my dream.. one more thing this is happening for past 4 years in my life but not every month regularly.. what will be the reason.. anyone pls explain