docstr: Forward function.
  
  Args:
      spec: (Batch, Length, Freq)
docstr_tok: ["Forward","function",".","Args",":","spec",":","(","Batch",",","Length",",","Freq",")"]
code: def forward(
      self, spec: torch.Tensor, spec_lengths: torch.Tensor = None
  ):
      """Forward function.
  
      Args:
          spec: (Batch, Length, Freq)
      """
  
      return mask_along_axis(
          spec,
          spec_lengths,
          mask_width_range=self.mask_width_range,
          dim=self.dim,
          num_mask=self.num_mask,
          replace_with_zero=self.replace_with_zero,
      )
  
file_path: espnet/espnet2/layers/mask_along_axis.py
imports: import math
  from typing import Sequence, Union
  import torch
  from typeguard import check_argument_types
label_desc: Use image node_id 3 for calling the MaskAlongAxis obj's underlying member method code with example usage: obj.forward(spec, spec_lengths) and returns: mask_along_axis