Brute force Python solution for Queens Chess Problem

Don't know if anyone is interested in this, but since i just finished my quick and dirty brute force solution of the Queens Chess Problem using Python i thought that maybe i should publish it to see what kind of feedback i will get:

#!/usr/bin/python3'''Program to solve the "n x n chess board and n queens chess problem" fromMagPi 68 (magpi.cc/JgrHLH)Date: 13MAY2018Author: raymond gordon'''import sys, copy, pprint


def is_solution(coordinates, dimensions):
   # check if multiple queens on same row   for x in range(dimensions):
  pos = coordinates[x]
   for next_col in range(x + 1, dimensions):
  next_pos = coordinates[next_col]
   # check if multiple queens on same row   if pos == next_pos:
   return None   # check if multiple queens on same diagonal   if (pos + next_col - x) == next_pos:
   return None  if (pos - next_col + x) == next_pos:
   return None  return coordinates


def main():
  solutions = []
   dim = 0   while True:
  dim = input('Enter the size of the chess board: ')
   if dim.isdecimal():
   break   print('An intiger value is required. ', end='')
  dim = int(dim)
   if dim < 4:
   print('No solution exists for a board of dimension', dim, 'x', dim)
   print('Exiting program ...')
   return   # populate this_permutation   this_permutation = []
   for n in range(dim):
  this_permutation.append(0)

   # calculate the number of permutations   possible_permutations = dim
   for n in range(dim):
  possible_permutations *= dim

   # initialize the counter  #placement_cnt = 0  # go through the permutations searching for all possible solutions   for n in range(possible_permutations):
  rem = n
   for m in range(dim):
  this_permutation[m] = rem % dim
  rem //= dim
   # is this_permutation a solution?   result = is_solution(copy.copy(this_permutation), dim)
   if result:
   # was this solution encountered previously?   if result not in solutions:
  solutions.append(result)

   print('\nInvestigated', possible_permutations, 'possibilities.')
  sol_cnt = len(solutions)
   print(sol_cnt, 'solutions found.')

   print('\n==========\nSolutions:\n==========')
   print('\n("x" position is position of value in array.\n"y" position is value in array)\n')
  cnt = 0   for solution in solutions:
  cnt += 1   print()
   print('Solution', cnt, ':')
  pprint.pprint(solution)


if __name__ == '__main__':
  main()

Unfortunately, the code is not being formatted properly here, so it is probably completely hopeless to understand.

- raymond