Is There an Upward Trend?

Create a function that determines if there is an upward trend.

Examples

upward_trend([1, 2, 3, 4]) ➞ True

upward_trend([1, 2, 6, 5, 7, 8]) ➞ False

upward_trend([1, 2, 3, "4"]) ➞ "Strings not permitted!"

upward_trend([1, 2, 3, 6, 7]) ➞ True

Notes

• If there is a string element in the list, return "Strings not permitted!".
• The numbers don't have to be consecutive (e.g. [1, 3, 5] should still return True).