Dynamic RLS DAX Syntax Errors - IF Function

I am trying to create a DAX expression for a Dynamic RLS design but keep receiving a syntax error.

The two tables used in the expression are a Users_tbl and a Permissions_Table.  The Users_tbl has a 1 : Many relationship with the Permissions Table.

Filters are applied based off of the values in the Permissions_Table[Senior Manager_RLS] column.

Several users have the word "None" listed in the [Senior Manager_RLS] column since I want those users to be able to see all data in the dashboard (no filters applied).  For everyone else, I want them to see only the levels I have assigned in the Senior Manager_RLS column.

I've been trying to implement an if statement to remove the filters if the Permissions_Table[Senior Manager_RLS] column contains "None" but keep receiving a syntax error on 'if' (I've tried both 'IF' and 'if' both returning the same syntax error).  Here is the complete code:

var temp_table = FILTER(Permissions_Table, Permissions_Table[Email]=USERPRINCIPALNAME())

if(temp_table[Senior Manager_RLS]="None",
TRUE,
[Email]=USERPRINCIPALNAME()
)

Any help would be much appreciated!