Update doc: One extra example about storing files (#18)

docs/source/index.rst

@@ -14,7 +14,7 @@ Usage of the AiiDA-Python plugin is straightforward. To get started, you need to
 
 It's important to note that the AiiDA-Python plugin is currently in the early stages of development. However, it is actively maintained and continuously improved to provide a reliable and efficient solution for executing Python code on remote computers.
 
-To learn more about using the AiiDA-Python plugin and its capabilities, please refer to the ``usage.rst`` file in this documentation.
+To learn more about using the AiiDA-Python plugin and its capabilities, please refer to the :ref:`usage.rst` file in this documentation.
 
 .. note::
 

docs/source/usage.rst

@@ -69,6 +69,41 @@ And therefore the smallest eigenvalue of the original matrix.
 
             self.outputs.value = np.average((H @ vec) / vec)
 
+File Storing
+------------
+
+Very often one wants to use SinglefileData file and directly store the file in the working directory of the code. In ``aiida-python`` there is an easy shortcut to do it with doc strings:
+
+.. code-block:: python
+
+    class ClassThatCannotStartWithTestCopyFile(CalcJobPython):
+        @classmethod
+        def define(cls, spec):
+            super().define(spec)
+
+            spec.input('repeats', valid_type=Int)
+            spec.input('inputfile', valid_type=SinglefileData)
+            spec.output('value', valid_type=Float)
+            spec.output('output', valid_type=SinglefileData)
+
+        def run_python(self):
+            """
+            This is commentary
+
+            This file will be stored in the working directory:
+            !file inputfile: data
+
+            Unset ports will be ignored:
+            !file inputfile2: data2
+
+            Store output
+            !!file output: output
+            """
+
+            # Code comes here
+
+
+
 More Examples
 -------------