N-Queens - Incomplete

#Snapshot of exact code at the end of the test.

#I wanted to first find all solutions to place N queen such no two queens threaten each other
#From that, I can then find a max threat

#Hardcoding due to insufficient time
N = 4
#{3,1,4, 1}
board = [
          [0, 0, 1, 0],
          [1, 0, 0, 0],
          [0, 0, 0, 1],
          [0, 1, 0, 0],
        ]

def solve_until(board, col):
  """
  Recurse function to solve the problem using backtracking. Not a good solution for big N
  """
  if col >= 4:
    return True

  for i in xrange(N):
    if is_safe(board, i, col):
      board[i][col]= 1;
      if solve_until(board, col+1):
        return true;
      board[i][col]=0

  return False

def is_safe(board, row, col):
  """
    Check is it safe to put queen on board. INCOMPLETE
  """
  for i in xrange(col):
    return bool(board[row][i])
  for i in xrange(row, N):
    for j in xrange(col, 0, -1):
      return bool(board[i][j])
  return True