Buggy python submission (verdict: Runtime Error):
# coding: utf-8
import sys
import numpy as np

sr = lambda: sys.stdin.readline().rstrip()
ir = lambda: int(sr())
lr = lambda: list(map(int, sr().split()))

MOD = 10 ** 9 + 7

def cmb(n, k):
    if k < 0 or k > n: return 0 
    return fact[n] * fact_inv[k] % MOD * fact_inv[n-k] % MOD

def cumprod(arr, MOD):
    L = len(arr); Lsq = int(L**.5+1)
    arr = np.resize(arr, Lsq**2).reshape(Lsq, Lsq)
    for n in range(1, Lsq):
        arr[:, n] *= arr[:, n-1]; arr[:, n] %= MOD
    for n in range(1, Lsq):
        arr[n] *= arr[n-1, -1]; arr[n] %= MOD
    return arr.ravel()[:L]

def make_fact(U, MOD):
    x = np.arange(U, dtype=np.int64); x[0] = 1
    fact = cumprod(x, MOD)
    x = np.arange(U, 0, -1, dtype=np.int64); x[0] = pow(int(fact[-1]), MOD-2, MOD)
    fact_inv = cumprod(x, MOD)[::-1]
    return fact, fact_inv

U = 2 * 10 ** 6 + 2  # 階乗テーブルの上限
fact, fact_inv = make_fact(U, MOD)

r1, c1, r2, c2 = lr()
answer = cmb(r2+c2+2, r2+1) - 1
answer -= cmb(r2+c1+1, r2+1) - 1
answer -= cmb(r1+c2+1, c2+1) - 1
answer += cmb(r1+c1, r1) - 1
print(answer % MOD)
# 26

Fixed submission:
import sys
import numpy as np

sr = lambda: sys.stdin.readline().rstrip()
ir = lambda: int(sr())
lr = lambda: list(map(int, sr().split()))

def cmb(n, k):
    return fact[n] * fact_inv[k] % MOD * fact_inv[n-k] % MOD

def cumprod(arr, MOD):
    L = len(arr); Lsq = int(L**.5+1)
    arr = np.resize(arr, Lsq**2).reshape(Lsq, Lsq)
    for n in range(1, Lsq):
        arr[:, n] *= arr[:, n-1]; arr[:, n] %= MOD
    for n in range(1, Lsq):
        arr[n] *= arr[n-1, -1]; arr[n] %= MOD
    return arr.ravel()[:L]

def make_fact(U, MOD):
    x = np.arange(U, dtype=np.int64); x[0] = 1
    fact = cumprod(x, MOD)
    x = np.arange(U, 0, -1, dtype=np.int64); x[0] = pow(int(fact[-1]), MOD-2, MOD)
    fact_inv = cumprod(x, MOD)[::-1]
    return fact, fact_inv

r1, c1, r2, c2 = lr()
MOD = 10 ** 9 + 7
U = 2 * 10 ** 6 + 10
fact, fact_inv = make_fact(U,MOD)

answer = cmb(r2+c2+2, r2+1) - cmb(r2+1+c1, r2+1) - cmb(r1+c2+1, r1) + cmb(r1+c1, r1)
print(answer % MOD)

# 16

Buggy python submission (verdict: Runtime Error):
import sys
import numpy as np

sr = lambda: sys.stdin.readline().rstrip()
ir = lambda: int(sr())
lr = lambda: list(map(int, sr().split()))

def cmb(n, k):
    return fact[n] * fact_inv[k] % MOD * fact_inv[n-k] % MOD

def cumprod(arr, MOD):
    L = len(arr); Lsq = int(L**.5+1)
    arr = np.resize(arr, Lsq**2).reshape(Lsq, Lsq)
    for n in range(1, Lsq):
        arr[:, n] *= arr[:, n-1]; arr[:, n] %= MOD
    for n in range(1, Lsq):
        arr[n] *= arr[n-1, -1]; arr[n] %= MOD
    return arr.ravel()[:L]

def make_fact(U, MOD):
    x = np.arange(U, dtype=np.int64); x[0] = 1
    fact = cumprod(x, MOD)
    x = np.arange(U, 0, -1, dtype=np.int64); x[0] = pow(int(fact[-1]), MOD-2, MOD)
    fact_inv = cumprod(x, MOD)[::-1]
    return fact, fact_inv

r1, c1, r2, c2 = lr()
MOD = 10 ** 9 + 7
U = 10 ** 6 + 10
fact, fact_inv = make_fact(U,MOD)

answer = cmb(r2+c2+2, r2+1) - cmb(r2+1+c1, r2+1) - cmb(r1+1+c2, r1) + cmb(r1+c1, r1)
print(answer)

# 16

Fixed submission:
import sys
import numpy as np

sr = lambda: sys.stdin.readline().rstrip()
ir = lambda: int(sr())
lr = lambda: list(map(int, sr().split()))

def cmb(n, k):
    return fact[n] * fact_inv[k] % MOD * fact_inv[n-k] % MOD

def cumprod(arr, MOD):
    L = len(arr); Lsq = int(L**.5+1)
    arr = np.resize(arr, Lsq**2).reshape(Lsq, Lsq)
    for n in range(1, Lsq):
        arr[:, n] *= arr[:, n-1]; arr[:, n] %= MOD
    for n in range(1, Lsq):
        arr[n] *= arr[n-1, -1]; arr[n] %= MOD
    return arr.ravel()[:L]

def make_fact(U, MOD):
    x = np.arange(U, dtype=np.int64); x[0] = 1
    fact = cumprod(x, MOD)
    x = np.arange(U, 0, -1, dtype=np.int64); x[0] = pow(int(fact[-1]), MOD-2, MOD)
    fact_inv = cumprod(x, MOD)[::-1]
    return fact, fact_inv

r1, c1, r2, c2 = lr()
MOD = 10 ** 9 + 7
U = 2 * 10 ** 6 + 10
fact, fact_inv = make_fact(U,MOD)

answer = cmb(r2+c2+2, r2+1) - cmb(r2+1+c1, r2+1) - cmb(r1+c2+1, r1) + cmb(r1+c1, r1)
print(answer % MOD)

# 16

Buggy python submission (verdict: Runtime Error):
import sys
from math import factorial

sr = lambda: sys.stdin.readline().rstrip()
ir = lambda: int(sr())
lr = lambda: list(map(int, sr().split()))

N = ir()
K = ir()
length = len(str(N))

def F(length, K, N):
    if length < K:
        return 0
    if K == 0:
        return 1
    if length == 1: #この時、Kも1
        return N
    ret = 0
    top = int(str(N)[0])
    if length-K >= 1:
        ret += factorial(length-1) // factorial(K) // factorial(length-K-1) * 9 ** K # 一個前まで    
    ret += factorial(length-1) // factorial(K-1) // factorial(length-K) * (top-1) * 9 ** (K-1) # 一桁目がtopより小さい数  
    # 一桁目がtopと同じ数
    if K > 1: 
        N = int(str(N)[1:])
        length = len(str(N))
        ret += F(length, K-1, N)
    else:
        ret += 1 # 2000のような数
    return ret

answer = F(length, K, N)
print(answer)


Fixed submission:
import sys
import numpy as np

sr = lambda: sys.stdin.readline().rstrip()
ir = lambda: int(sr())
lr = lambda: list(map(int, sr().split()))

def cmb(n, k):
    return fact[n] * fact_inv[k] % MOD * fact_inv[n-k] % MOD

def cumprod(arr, MOD):
    L = len(arr); Lsq = int(L**.5+1)
    arr = np.resize(arr, Lsq**2).reshape(Lsq, Lsq)
    for n in range(1, Lsq):
        arr[:, n] *= arr[:, n-1]; arr[:, n] %= MOD
    for n in range(1, Lsq):
        arr[n] *= arr[n-1, -1]; arr[n] %= MOD
    return arr.ravel()[:L]

def make_fact(U, MOD):
    x = np.arange(U, dtype=np.int64); x[0] = 1
    fact = cumprod(x, MOD)
    x = np.arange(U, 0, -1, dtype=np.int64); x[0] = pow(int(fact[-1]), MOD-2, MOD)
    fact_inv = cumprod(x, MOD)[::-1]
    return fact, fact_inv

r1, c1, r2, c2 = lr()
MOD = 10 ** 9 + 7
U = 2 * 10 ** 6 + 10
fact, fact_inv = make_fact(U,MOD)

answer = cmb(r2+c2+2, r2+1) - cmb(r2+1+c1, r2+1) - cmb(r1+c2+1, r1) + cmb(r1+c1, r1)
print(answer % MOD)

# 16