   end
 
   @doc """
-  Concatenates two binaries.
+  Concatenates two binaries. Allowed in guard clauses.
 
   ## Examples
 


  @doc """
  Works like `binary_to_atom` but the atom must exist.

  ## Examples



  @doc """
  Returns a binary which corresponds to the text representation
  of `some_atom` in UTF8 encoding. Allowed in guard clauses.

  ## Examples

