I have added a case where we move both pointers if the end value is the same.

```
def merge(intervals_a, intervals_b):
result = []
# This essentially just helps us to make the subsequent selection of intervals more semantic
start, end = 0, 1
i, j = 0, 0
# Continue running the loop until both indices of each list are in range
while i < len(intervals_a) and j < len(intervals_b):
# Grab the smallest end of both intervals, this is just to aid readability further down
smallest_end = min(intervals_a[i][end], intervals_b[j][end])
# Check if the interval from the first list overlaps the interval from the second list
if intervals_a[i][start] >= intervals_b[j][start] and intervals_a[i][start] <= intervals_b[j][end]:
result.append([intervals_a[i][start], smallest_end])
# Check if the interval from the second list overlaps the interval from the first list
elif intervals_b[j][start] >= intervals_a[i][start] and intervals_b[j][start] <= intervals_a[i][end]:
result.append([intervals_b[j][start], smallest_end])
# If the end of both intervals is equal to each other, since we know that intervals
# in each list are disjoint this means both the start and end values from an interval
# in each list are smallest than the next interval in the same list
# using that information we can safely move both index pointers of each list up by 1
if intervals_a[i][end] == intervals_b[j][end]:
i += 1
j += 1
elif intervals_a[i][end] < intervals_b[j][end]:
i += 1
else:
j += 1
return result
```

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