code: def _in_projection(
      q,
      k,
      v,
      w,
      b=None,
  ):
      """Projects query, key and value efficiently, depending on whether we are
      doing self- attention (query is key is value) or cross-attention (key is
      value) or an attention where query, key and value are all different.
  
      it is only used in
      multi_head_attention layer.
      This helper function is a modified version of https://github.com/pytorch/pytorch/b
      lob/5293dee9208cc0e1e7db2ebdcbaef64908c087c6/torch/nn/functional.py#L4762.
      """
      E = q.shape[-1]
      if k is v:
          if q is k:
              # self-attention
              proj = ivy.linear(q, w, bias=b)
              proj = proj.split(num_or_size_splits=3, axis=-1)
              return proj[0], proj[1], proj[2]
          else:
              # encoder-decoder attention
              w_q, w_kv = w.split(num_or_size_splits=[E, E * 2])
              if b is None:
                  b_q = b_kv = None
              else:
                  b_q, b_kv = b.split([E, E * 2])
              q_proj = ivy.linear(q, w_q, bias=b_q)
              kv_proj = ivy.linear(k, w_kv, bias=b_kv)
              kv_proj = kv_proj.split(num_or_size_splits=2, axis=-1)
              return (q_proj, kv_proj[0], kv_proj[1])
      else:
          w_q, w_k, w_v = w.split(num_or_size_splits=3)
          if b is None:
              b_q = b_k = b_v = None
          else:
              b_q, b_k, b_v = b.split(num_or_size_splits=3)
          return (
              ivy.linear(q, w_q, bias=b_q),
              ivy.linear(k, w_k, bias=b_k),
              ivy.linear(v, w_v, bias=b_v),
          )
  
imports: from typing import Optional, Tuple, Union, Sequence
  import ivy
  from ivy.utils.backend import current_backend
  from ivy.func_wrapper import handle_array_function, handle_partial_mixed_function, inputs_to_ivy_arrays, to_native_arrays_and_back, inputs_to_native_shapes, handle_out_argument, handle_nestable, handle_array_like_without_promotion, handle_device, handle_backend_invalid
  from ivy.utils.exceptions import handle_exceptions
label_desc: Use image node_id 2 for calling a global function with example usage: _in_projection(q, k, v, w, b) and returns: ivy,  ivy,  ivy, proj,  proj,  proj, q_proj,  kv_proj,  kv_proj