Write a function that input a dna string and outputs the complementary dna

Question

a. Write a function, dna_strand, that accepts a string representing one side of the dna and returns the other complementary side. In DNA strings, symbols "A" and "T" are complements of each other, as "C" and "G".
b. Using your function from part a), write a program that inputs a dna string and outputs the complementary dna. See sample runs below.
Sample Run 1:
Enter dna: CATGA
dna complement: GTACT
Sample Run 2:
Enter dna: AAGGTTCC
dna complement: TTCCAAGG
Sample Run 3:
Enter dna: ATTTTGGCCCATATAT
dna complement: TAAAACCGGGTATATA

So I have been trying to use the function that i wrote but it seems i cant figure out how to do part b.
Thats my code so far:

def dna_strand(n):
if n=="A":
print("T")
elif n=="T"
print("A")
elif n=="C"
print("G")
elif n=="G"
print("C")

n = str(input("Enter dna:"))
new_dna = str(input("Enter dna:"))

How do you think I should continue ?

Answer 1

I added this to my code but now it wants me to write to DNA string, but i want my function to do it.

Answer 2

output error

Answer 3

You need to loop over the dna string and call the dna_strand for each nucleotide

for n in new_dna:
dna_strand(n)