Is it correct to have 'a' before a proper noun? [duplicate]

According to my knowledge, the indefinite article 'a' must never be used before a proper noun. But I recently heard the English sentence: "Every civilian should be a Mahatma Gandhi to his society".

As per my knowledge, "Mahatma Gandhi" is a proper noun here and 'a' is the article.

Believing the speaker to have a good grasp of English, I now have this doubt: are there any occasions where it is proper to have an indefinite article before a proper noun?

Please advise me.

Solution 1:

The 'rule' is as usual better termed a 'guideline'.

There are not uncommon occasions when there is not the usual definiteness attaching to the referent (actual thing being named by) a proper noun. Thus:

There's a London in Canada and eight Londons in the US.

There's a Jack Robinson who lives on our street.

We've just bought a Dyson.

As Jasper indicates, this includes metaphorical usages (which 'Dyson' arguably still is):

He's never going to be a Denis Law / He's no Denis Law.

Solution 2:

Mahatma Ghandi here refers to a person with his qualities. It does not literally mean Mahatma Ghandhi himself. In this case, the use of a is correct. Another example:

We cannot expect everyone to be a Gautama Buddha or a Jesus Christ.