Password Generator (Write to File)

#generates 1000 random 10 digit number passwords and writes to a file
import random
counter=0
print("please wait...")
while True:
    randnum = random.randint(1000000000, 9999999999)
    myobj=open("passwords.txt", "a")
    myobj.write(str(randnum) + "\n")
    myobj.close()
    counter=counter+1
    if counter == 1000:
        break