input: Write a function to create an object-oriented structure in Python to solve a maze. The function should initialize a Maze object with dimensions n and m, and the solve_maze method should find and return the path from the start point (top-left corner) to the end point (bottom-right corner) if a path exists. If no path exists, it should return an empty list.
  
  class Maze:
      def __init__(self, n, m):
          self._n, self._m = n, m
          self._grid = [[None] * m for _ in range(n)]
  
      def solve_maze(self):
          result, found = [], False
          start, end = (0, 0), (self._n-1, self._m-1)
  
          for i in range(self._n):
              for j in range(self._m):
                  if self._grid[i][j] == 1:
                      value = 0
                      self._find_omega(i, j, value, result, start, end,
                                       found)
                      return result
  
      def _find_omega(self, i, j, value,
                      result, start, end, found):
          rowNbr, colNbr = [-1, 0, 0, 1], [0, -1, 1, 0]
  
          if (i, j) == end:
              found = True
              result.append(value)
              return
  
          if found == True:
              return
  
          self._grid[i][j] = 0
          for k in range(4):
              if self._on_board(i + rowNbr[k], j + colNbr[k]):
                  self._find_omega(i + rowNbr[k], j + colNbr[k],
                                   value + 1, result,
                                   start, end, found)
  
      def _on_board(self, i, j):
          return 0 <= i < self._n and 0 <= j < self._m and self._grid[i][j] == 1
  
  assert Maze(5, 5).solve_maze() == []
  assert Maze(3, 4).solve_maze() == []
  assert Maze(2, 2).solve_maze() == []
  assert Maze(4, 3).solve_maze() == []
  assert Maze(1, 1).solve_maze() == []
output: def solve_maze(self):
      result, found = [], False
      start, end = (0, 0), (self._n-1, self._m-1)
  
      def dfs(i, j):
          nonlocal found
          if (i, j) == end:
              found = True
              result.append((i, j))
              return
  
          if found:
              return
  
          self._grid[i][j] = 0
          for di, dj in [(-1, 0), (0, -1), (0, 1), (1, 0)]:
              ni, nj = i + di, j + dj
              if self._on_board(ni, nj):
                  dfs(ni, nj)
                  if found:
                      result.append((i, j))
                      return
  
      dfs(0, 0)
      return result[::-1] if found else []