1. Multiplication

Write a Python function to multiply all the positive numbers in a list. The function should return that result.

2. Function updates

Write a python function that transforms all the positive numbers from a list and returns back True if it performed any action on the list and False otherwise.

3. Palindrome

Write a function that returns True if its argument is a palindrome and False otherwise. A palindrome is a word, number, phrase, or other sequence of characters which reads the same way backward as forward (e.g., madam, Able was I ere I saw Elba, 10101, 90.09).

4. k-mer counting

Remember Exercise 2 (Analyse a repeat structure) from yesterday's assignment?

We are going to make a repeating DNA sequence and extract some subsequences
from it.
- Make a short tandem repeat that consists of three "ACGT" units and five
  "TTATT" units.
- Print all suffixes of the repeat structure.
  - **Note**: A suffix is an ending. For example, the word "spam" has five
  suffixes: "spam", "pam", "am", "m" and "".
- Print all substrings of length 3.
- Print all unique substrings of length 3.

**Hint**: All elements in a set are unique.

(1/2)

Perform the following:

Make a function from your implementation.
Have k as an argument to the function.
Test the function on several input strings.

(2/2)

Modify your function to use a dictionary with substring counts.