Как исправить ошибку: ValueError: setting an array element with a sequence

import numpy as np
 
nt = 100
eps = 0.001
 
def Fi(N1, bet11, bet12, N2):
    return (bet11 - bet12 * N2) * N2
 
def Ksi(N1, N2, bet21):
    return N1 * N2 * bet21
 
def Jbet(N1, N2, F1, F2): 
    y = 0
    k = 0
    for i in range(nt): 
        if (i % 5 == 0): 
            k = k + 1
            y = y +((F1[i] - N1[i])* (F1[i] - N1[i])) + ((F2[i] - N2[i])* (F2[i] - N2[i]))
    return(y)
 
def z1(N1, N2, bet11, bet12, bet21):
    N1 = np.insert(N1, 0, 1.8)
    N2 = np.insert(N2, 0, 1.8)
 
    for i in range(nt):
        h = 28.0 / 100.0
        k0 = Fi(N1, bet11, bet12, N2)
        l0 = Ksi(N1, N2, bet21)
 
        k1 = Fi(N1 + (h / 2.0) * k0, bet11, bet12, N2 + (h / 2.0) * l0)
        l1 = Ksi(N1 + (h / 2.0) * k0, N2 + (h / 2.0) * l0, bet21)
 
        k2 = Fi(N1 + (h / 2.0) * k1, bet11, bet12, N2 + (h / 2.0) * l1)
        l2 = Ksi(N1 + (h / 2.0) * k1, N2 + (h / 2.0) * l1, bet21)
 
        k3= Fi(N1 + h * k2, bet11, bet12, N2 + h * l2)
        l3 = Ksi(N1 + h * k2, N2 + h * l2, bet21)
 
        N1[i + 1] = N1[i] + (h / 6.0) * (k0 + 2.0 * k1 + 2.0 * k2 + k3)
        N2[i + 1] = N2[i] + (h / 6.0) * (l0 + 2.0 * l1 + 2.0 * l2 + l3)
        return N1, N2
 
N1 = np.array(nt + 1, dtype=float)
N2 = np.array(nt + 1, dtype=float)
 
F1 = np.array(nt + 1, dtype=float)
F2 = np.array(nt + 1, dtype=float)
 
bet11 = 0.5
bet12 = 0.5
bet21 = 0.6
 
z1(N1, N2, bet11, bet12, bet21)
print(z1(N1, N2, bet11, bet12, bet21))
 
for i in range(nt):
    if (i % 5 == 0): 
        F1[i] = N1[i]
        F2[i] = N2[i]
    
    else:
        F1[i] = 0
        F2[i] = 0
    
Jb = 1
 
it = 0
bet11 = 0.3
bet12 = 0.3
bet21 = 0.4
 
while Jb > eps:
    z1(N1, N2, bet11, bet12, bet21)
    Jb = Jbet(N1, N2, F1, F2)
    print(Jb)
    print(it)
    it = it + 1