local / global lists

[RedWuff]

So I coded a Program in python whith PyGameZero and the mu editor

def animate_nodes():
    for current_node in node_list:
        x = current_node[0] + current_node[2]
        y = current_node[1] + current_node[3]
        
        if current_node[2] > 0 and current_node[2] < 10:
            vx = current_node[2] + random.randrange(-1, 1)
            
        if current_node[3] > 0 and current_node[3] < 10:
            vx = current_node[3] + random.randrange(-1, 1)
        
        new_node_list.append = [x, y, vx, vy]
    
    node_list = new_node_list.copy()

This is one part of my programm.
Now Im getting this error:
UnboundLocalError: local variable 'node_list' referenced before assignment

Now I now what global and local variables are but the variable node_list is a global one in my program so I don't understand why this happens.

for better context here the whole code (its supposed to animate a few nodes that get connected when they are in a particular range to each other and move the nodes by a few pixel every frame):

import random
import math

WIDTH = 1280
HEIGHT = 720

# defines the number of nodes visible on the screen (+ 1)
node_count = 30

# defines the range in which the nodes will connect
connection_range = 150

# stores the x and y coordinates of the nodes
node_list = []

# stores the x and y values of the vectors
connection_list = []

others_list = []
    
# creates the nodes
for i in range(0, node_count):
    # generate random coordinates
    x = random.randrange(1, 1280)
    y = random.randrange(1, 720)
    vx = random.randrange(0, 10)
    vy = random.randrange(0, 10)
    # adds these x and y values to the nodelist
    node_list.append([x, y])
    
    


def calculate_connections():
    others_list = node_list.copy()
    # after we have created the nodes we go over the nodes one by one
    for current_point in others_list:
        
        others_list.remove(current_point)
        # then we look at all the resting nodes (except for the current one) and we compare the distances
        # this is a so called nested loop (verschachtelte Schleife)
        
        for other_point in others_list:

        # coords_temp = []
            x_temp = other_point[0]
            y_temp = other_point[1]
            x = current_point[0]
            y = current_point[1]

            # calculate the vector between the current and the other nodes
            vector_x = abs((x - x_temp))
            vector_y = abs((y - y_temp))

            vector_length = math.sqrt(vector_x ** 2 + vector_y ** 2)
            
            print(vector_length)
            # compare set connection range to vector range
            if vector_length <= connection_range:
                connection_temp = []
                connection_temp.append([x, y])
                connection_temp.append([x_temp, y_temp])
                connection_list.append(connection_temp)

def animate_nodes():
    for current_node in node_list:
        x = current_node[0] + current_node[2]
        y = current_node[1] + current_node[3]
        
        if current_node[2] > 0 and current_node[2] < 10:
            vx = current_node[2] + random.randrange(-1, 1)
            
        if current_node[3] > 0 and current_node[3] < 10:
            vx = current_node[3] + random.randrange(-1, 1)
        
        new_node_list.append = [x, y, vx, vy]
    
    node_list = new_node_list.copy()
    

# draws the Frame
def draw():
    calculate_connections()
    # draw the background
    screen.fill((255, 255, 255))

    # draws the nodes
    for i in range(node_count):
        screen.draw.filled_circle(node_list[i-1], 3, (125, 125, 125))

    # draw the connections
    for line in connection_list:
        print(line)
        screen.draw.line(line[0], line[1], (0, 0, 0))
        
    animate_nodes()

I hope you can help me :)
thanks in advance <3