def months_to_reach_target(principal, interest_percentage_per_annum, target):
    """Returns months needed to reach investment goal."""
initial_principal = 0
interest_rate_per_annum = 0.10
end_target = 0

interest_rate_per_month = interest_rate_per_annum / 12
principal = initial_principal
num_months = 0

while principal < target + initial_principal:
    increase = principal * interest_rate_per_month
    principal = principal + increase
    num_months += 1

""" Test args"""
print(months_to_reach_target(100, 10, 200))
print(months_to_reach_target(100, 30, 130))