Spark UDF error



I have created a UDF (user defined function) like so:
val myAppend: String=>String=_ + “_000”
It just appends to an existing string.

Now when I use it on a string column, I get error:“callsign”))).as(“Sign”).show
:39: error: type mismatch;
found : org.apache.spark.sql.Column
required: String“callsign”))).as(“New”).show

How can I take a column of data and simply append to each value?