expression in ms access

This expression in search query is not giving any results.

code and code2 are combo boxes in the search form, CS_Code is a table column.

[CS_Code]=([Forms]![Search Form]![code] Or
 [Forms]![Search Form]![code2]) Or
 ( [Forms]![Search Form]![code] Is Null Or
   [Forms]![Search Form]![code2] Is Null )
 

I am trying to get entries (search results) from table when CS_code is equal to code or code2

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