import math


def exponential_type_curve(initial_prod=0, di_factor=0.15, time=10):
    """Creates a type curve using Arp's equation for exponential decline. Make sure the units for production and time are the same.
    The input for time is how long you want the type curve to estimate for, for example 1 year or 10 years. The function
    returns the type curve as a list."""
    production = []
    for x in range(0, time + 1):
        q_time = (initial_prod)*math.exp(-di_factor*x)
        production.append(q_time)
    return production