CONTAINS Returns true if values for all referred columns exist, or are contained, in those columns; otherwise, the function returns false.
Syntax
CONTAINS(table, columnName, value[, columnName, value]…)
Parameters
Table – Any DAX expression that returns a table of data.
ColumnName – The name of an existing column, using standard DAX syntax. It cannot be an expression.
Value – Any DAX expression that returns a single scalar value, that is to be sought in columnName. The expression is to be evaluated exactly once and before it is passed to the argument list.
Return Value
A value of TRUE if each specified value can be found in the corresponding columnName, or are contained, in those columns; otherwise, the function returns FALSE.
Reference Data
https://docs.microsoft.com/en-us/dax/dax-function-reference