code: def flatten(input, start_dim=0, end_dim=-1):
      return ivy.flatten(input, start_dim=start_dim, end_dim=end_dim)
  
imports: import ivy
  from ivy.func_wrapper import with_unsupported_dtypes, with_supported_dtypes
  from ivy.functional.frontends.torch.func_wrapper import to_ivy_arrays_and_back
  from ivy.functional.frontends.torch import promote_types_of_torch_inputs
  import ivy.functional.frontends.torch
label_desc: Use image node_id 21 for calling a global function with example usage: flatten(input, start_dim, end_dim) and returns: ivy