SQL Script

I have written the following function but when I try to run it, I get Error:
ERROR:  parser: parse error at or near "". As you can see, there is no
instance of "" in my function. Does anyone have any idea why this is
happening?

CREATE FUNCTION dropifexists(text)
RETURNS text
AS 'DECLARE
   numcount integer;
   nameoftable text;
BEGIN
   nameoftable := lower($1);
   SELECT INTO numcount count(tablename)
   FROM pg_tables
   WHERE tablename = nameoftable;

   if numcount = 1
   then DROP TABLE nameoftable;
   end if;
   RETURN nameoftable;
END;'