# Search for a matching String val in the array vals.
# If found, return index. If not found, return None.
def eSearch(val, items):

    # Loop over all items in the list
    i = 0
    while i < len(items):
        # Compare items
        if val == items[i]:
            return i
        i += 1

    # If we get this far, val was not found.
    return None