class_docstr: Identity operation that does nothing. Sometimes useful as a placeholder for
  another Module.
docstr: **Arguments:**
  
  - `x`: The input, of any type.
  - `key`: Ignored; provided for compatibility with the rest of the Equinox API.
      (Keyword only argument.)
  
  **Returns:**
  
  The input, unchanged.
docstr_tok: ["*","*","Arguments",":","*","*","-","`","x","`",":","The","input",",","of","any","type",".","-","`","key","`",":","Ignored",";","provided","for","compatibility","with","the","rest","of","the","Equinox","API",".","(","Keyword","only","argument",".",")","*","*","Returns",":","*","*","The","input",",","unchanged","."]
code: def __call__(
      self, x: _T, *, key: Optional[PRNGKeyArray] = None
  ) -> _T:
      """**Arguments:**
  
      - `x`: The input, of any type.
      - `key`: Ignored; provided for compatibility with the rest of the Equinox API.
          (Keyword only argument.)
  
      **Returns:**
  
      The input, unchanged.
      """
      return x
  
file_path: equinox/equinox/nn/_linear.py
imports: import math
  from typing import Any, Literal, Optional, TypeVar, Union
  import jax
  import jax.numpy
  import jax.random
  from jaxtyping import Array, PRNGKeyArray
  from .._module import field, Module
label_desc: Use image node_id 2 for calling the Identity obj's underlying member method code with example usage: obj.__call__(x) and returns: x