title: Source code for a function which is not an s4 generic
body: <p>I need to see the source code for the ExtractLambdas function which is used internally in <strong>mirt</strong> package.</p>
  
  <p>I have tried following things:
  1)</p>
  
  <pre><code>showMethods("ExtraLambdas")
  
  Function "ExtraLambdas":
   &lt;not an S4 generic function&gt;
  </code></pre>
  
  <p>2)</p>
  
  <pre><code>getAnywhere(ExtractLambdas)
  A single object matching ‘ExtractLambdas’ was found
  It was found in the following places
    namespace:mirt
  with value
  
  function (x) 
  standardGeneric("ExtractLambdas")
  &lt;bytecode: 0x0000000044248898&gt;
  &lt;environment: 0x000000005a3a3750&gt;
  attr(,"generic")
  [1] "ExtractLambdas"
  attr(,"generic")attr(,"package")
  [1] "mirt"
  attr(,"package")
  [1] "mirt"
  attr(,"group")
  list()
  attr(,"valueClass")
  character(0)
  attr(,"signature")
  [1] "x"
  attr(,"default")
  `\001NULL\001`
  attr(,"skeleton")
  (function (x) 
  stop("invalid call in method dispatch to 'ExtractLambdas' (no default method)", 
      domain = NA))(x)
  attr(,"class")
  [1] "standardGeneric"
  attr(,"class")attr(,"package")
  [1] "methods"
  </code></pre>
  
  <p>Still I am unable to get the code for <code>ExtraLambdas</code>. Please help.
  thanks in advance.</p>