def is$\_$prime $($ a $)$:

# a is an integer

if a $==1$:

return False

elif a $==2$ or a $==3$:

return True

result $=$ True

for i in range $(2,$ a $//2)$:

if a $\%$ i $==0$:

result $=$ False

return True

With regard to the function above:

$$What is its bigO time complexity? Very briefly justify your answer.

$$If you used any variables, such as N$,$in our time complexity, define them in term of the function$$s parameters.