An exception raised when a function is invoked that is not defined.

The following fields of this exception are public and can be accessed freely:

• :module (module/0) - the module name
• :function (atom/0) - the function name
• :arity (non_neg_integer/0) - the arity of the function

For example, if you try to call MyMod.non_existing_fun("hello", 1), the error would look like:

%UndefinedFunctionError{
  module: MyMod,
  function: :non_existing_fun,
  arity: 2,
  # Other private fields...
}