What Causes Bugs in Code?

# Define a function called BinarySearch that takes a list and an element
def BinarySearch(A, elem):
  left = 0  # Set the leftmost index to 0
  right = len(A)-1  # Set the rightmost index to the last index of the list
  
  # While the left index is less than the right
  while left < right:
    # Calculate the middle index by adding the left index to half of the difference between right and left indices
    mid = (right-left)//2+ left
    # If the middle element equals the target element
    if A[mid] == elem:
      return True  # Return True indicating that the element was found
    
    # If the middle element is greater than the target element
    if A[mid] > elem:
      right = mid-1  # Move the right boundary to the mid index - 1
      
    # If the middle element is less than the target element
    else:
      left = mid+1  # Move the left boundary to the mid index + 1
  
  # After all elements are checked and the target is not found, return False
  return False
# Create a test array
testArr1 = [1,2,3,4,5,6]
# Test the BinarySearch function with the number 3 (which is present in the list)
print(BinarySearch(testArr1, 3))  # Expected output: True
# Test the BinarySearch function with the number 5 (which is present in the list)
print(BinarySearch(testArr1, 5))  # Expected output: True
# Test the BinarySearch function with the number 10 (which is not present in the list)
print(BinarySearch(testArr1, 10))  # Expected output: False