text: """
  Copyright 2020 The OneFlow Authors. All rights reserved.
  
  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
  You may obtain a copy of the License at
  
      http://www.apache.org/licenses/LICENSE-2.0
  
  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.
  """
  import oneflow as flow
  from oneflow.framework.tensor import register_tensor_op
  from oneflow.nn.module import Module
  
  
  class Flatten(Module):
      """Flattens a contiguous range of dims into a tensor. For use with: nn.Sequential.
  
      Args:
          start_dim: first dim to flatten (default = 1).
          end_dim: last dim to flatten (default = -1).
      
  
      For example: 
  
      .. code-block:: python 
  
          >>> import oneflow as flow
          >>> input = flow.Tensor(32, 1, 5, 5)
          >>> m = flow.nn.Flatten()
          >>> output = m(input)
          >>> output.shape
          oneflow.Size([32, 25])
  
      """
  
      def __init__(self, start_dim: int = 1, end_dim: int = -1) -> None:
          super().__init__()
          self.start_dim = start_dim
          self.end_dim = end_dim
  
      def forward(self, input):
          return flow._C.flatten(input, start_dim=self.start_dim, end_dim=self.end_dim)
  
      def extra_repr(self) -> str:
          return "start_dim={}, end_dim={}".format(self.start_dim, self.end_dim)
  
  
  if __name__ == "__main__":
      import doctest
  
      doctest.testmod(raise_on_error=True)
  