Answer:
The function in Python is as follows:
def unite_lists(A, B):
union = []
for elem in A:
if elem in B:
union.append(elem)
return union
Step-by-step explanation:
This defines the function
def unite_lists(A, B):
This initializes an empty list for the union list
union = []
This iterates through list A
for elem in A:
This checks if the item in list A is in list B
if elem in B:
If it is present, the item is appended to the union list
union.append(elem)
This returns the union of the two lists
return union