ModuleNotFoundError:什么意思__main__不是一个包?

我正在尝试从控制台运行一个模块。我的目录结构是这样的:

我试图运行模块p_03_using_bisection_search.py，从problem_set_02目录使用:

$ python3 p_03_using_bisection_search.py

__abc0中的代码是:

__author__ = 'm'




from .p_02_paying_debt_off_in_a_year import compute_balance_after




def compute_bounds(balance: float,
annual_interest_rate: float) -> (float, float):


# there is code here, but I have omitted it to save space
pass




def compute_lowest_payment(balance: float,
annual_interest_rate: float) -> float:


# there is code here, but I have omitted it to save space
pass


def main():
balance = eval(input('Enter the initial balance: '))
annual_interest_rate = eval(input('Enter the annual interest rate: '))


lowest_payment = compute_lowest_payment(balance, annual_interest_rate)
print('Lowest Payment: ' + str(lowest_payment))




if __name__ == '__main__':
main()

我正在导入p_02_paying_debt_off_in_a_year.py中的函数，其代码为:

__author__ = 'm'




def compute_balance(balance: float,
fixed_payment: float,
annual_interest_rate: float) -> float:


# this is code that has been omitted
pass




def compute_balance_after(balance: float,
fixed_payment: float,
annual_interest_rate: float,
months: int=12) -> float:


# Omitted code
pass




def compute_fixed_monthly_payment(balance: float,
annual_interest_rate: float) -> float:


# omitted code
pass




def main():
balance = eval(input('Enter the initial balance: '))
annual_interest_rate = eval(
input('Enter the annual interest rate as a decimal: '))
lowest_payment = compute_fixed_monthly_payment(balance,
annual_interest_rate)
print('Lowest Payment: ' + str(lowest_payment))




if __name__ == '__main__':
main()

我得到以下错误:

ModuleNotFoundError: No module named '__main__.p_02_paying_debt_off_in_a_year'; '__main__' is not a package

我不知道如何解决这个问题。我已经尝试添加一个__init__.py文件，但它仍然不工作。