curriculum/challenges/english/blocks/learn-interfaces-by-building-an-equation-solver/662fc3eba556a6bf800d48c1.md
The isinstance() built-in function takes two arguments and returns a Boolean indicating if the object passed as the first argument is an instance of the class passed as the second argument.
isinstance(7, int) # True
Another thing you want to check is that every argument is a number. After your first if, create a for loop that iterates over args and checks if the argument at the current iteration is not an instance of int or float. Use the isinstance() function and pass it a tuple containing int and float as the second argument.
If the argument is not a number, raise a TypeError saying "Coefficients must be of type 'int' or 'float'".
You should create a for loop that iterates over args after your if statement.
({ test: () => assert(runPython(`_Node(_code).find_class("Equation").find_function("__init__").find_for_loops()[0].find_for_iter().is_equivalent("args")`)) })
You should create an if statement that checks if the current coefficient is not an instance of either int or float within the for loop.
({ test: () => assert(runPython(`
var = str(_Node(_code).find_class("Equation").find_function("__init__").find_for_loops()[0].find_for_vars())
cond1 = f'not isinstance({var}, (int, float))'
cond2 = f'not isinstance({var}, (float, int))'
if_stmt = _Node(_code).find_class("Equation").find_function("__init__").find_for_loops()[0].find_ifs()[0].find_conditions()[0]
if_stmt.is_equivalent(cond1) or if_stmt.is_equivalent(cond2)
`)) })
You should use the provided string to raise a TypeError within the if statement.
({ test: () => assert(runPython(`_Node(_code).find_class("Equation").find_function("__init__").find_for_loops()[0].find_ifs()[0].find_bodies()[0].has_stmt("raise TypeError(\\"Coefficients must be of type 'int' or 'float'\\")")
`)) })
from abc import ABC, abstractmethod
--fcc-editable-region--
class Equation(ABC):
degree: int
def __init__(self, *args):
if (self.degree + 1) != len(args):
raise TypeError(
f"'{self.__class__.__name__}' object takes {self.degree + 1} positional arguments but {len(args)} were given"
)
--fcc-editable-region--
def __init_subclass__(cls):
if not hasattr(cls, "degree"):
raise AttributeError(
f"Cannot create '{cls.__name__}' class: missing required attribute 'degree'"
)
@abstractmethod
def solve(self):
pass
@abstractmethod
def analyze(self):
pass
class LinearEquation(Equation):
degree = 1
def solve(self):
pass
def analyze(self):
pass
lin_eq = LinearEquation(2, 3)