Count execution time of my sorting method

'''
CHAPTER 1
'''
def selectionSort(A):
    n = len(A)
    for j in range(0, n-1):
        for i in range(j+1, n):
            if A[j] > A[i]:
                A[j], A[i] = A[i], A[j]

    return A

# MAIN FUNCTION - 1
myList = [2, 4, 5, 1, 6, 3]
print("Initial list: " + str(myList))
print("Sorted list with my method: " + str(selectionSort(myList)))
print("Sorted list with Python's default method: " + str(sorted(myList)))
print()

'''
CHAPTER 2
'''
import random
# Create a list of 3000 integers in range 1 .... 1000
newList = [random.randint(1, 1000) for i in range(3000)]
from timeit import default_timer as timer
executions = list(range(100, 3100, 100))
measurements = []
# executions = [100, 200, 300, ...., 2900, 3000]
print()
print("~~~~ This process will take less than 10 seconds. Just wait ~~~~")
print()
print()

for num in executions:
    start = timer()
    selectionSort(newList[0: num])
    end = timer()
    measurements.append(end - start)

print("Elements    Execution Time")
for i in range(len(executions)):
    print(str(executions[i]) + "        " + str(measurements[i] * 1000) + "ms")


'''
CHAPTER 3
'''

# Plots time
import matplotlib.pyplot as plt
plt.plot(executions, measurements)
plt.xlabel("Number of Elements")
plt.ylabel("Execution Time")