Write a function with signature: valid(text, chars="ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789") The function should return a (possibly empty) string which is a copy of text that only contains characters in...

Write a function with signature:

valid(text, chars="ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789")

The function should return a (possibly empty) string which is a copy of text

that only contains characters in chars. For example:

valid("Barking!") # Returns "B"

valid("KL754", "0123456789") # Returns "754"

valid("BEAN", "abcdefghijklmnopqrstuvwxyz") # Returns ""

It can be done in half a dozen lines, using a for loop and an if statement, not

counting the docstring, which should also be written.