docs: Add datetime explanation in the README

README.rst

@@ -41,17 +41,17 @@ A Simple Example
     data_range.set_background('#000000')          # set every cell backgrounds to black
     data_range.set_font_color('#ffffff')          # set every cell font colors to white
 
-For better security, you can also create your SpreadsheetApp object with
-environment variables instead of the `secrets.json` file.
 
-To obtain your secret json file and know more about how to initialize your ENV vars, you can refer to `the authentication tutorial`_.
+You can also create your SpreadsheetApp object with environment variables
+instead of the `secrets.json` file. You can refer to `the authentication tutorial`_ for more info.
 
 .. _the authentication tutorial: https://github.com/socialpoint-labs/sheetfu/blob/master/documentation/authentication.rst
 
-You can refer to the `sheetfu API documentation`_ for a more detailed description.
+Please read the `sheetfu API documentation`_ for a more detailed description.
 
 .. _sheetfu API documentation: https://github.com/socialpoint-labs/sheetfu/blob/master/documentation/usage.rst
 
+
 The Table module
 ----------------
 
@@ -86,6 +86,52 @@ You can refer to the `Table API documentation`_ for a more detailed description.
 .. _Table API documentation: https://github.com/socialpoint-labs/sheetfu/blob/master/documentation/table.rst
 
 
+Casting
+-------
+
+An effort has been made to guide Sheetu as a Google Sheet ORM, where any values
+found in a spreadsheet are casted to a matching Python object. Since version
+1.5.7, Sheetfu returns `DATE` and `DATE_TIME` as Python `datetime` object.
+Similarly, setting a cell with a `datetime` object will make the necessary
+parsing and casting to reflect those cells as `DATE_TIME` in the sheet.
+
+.. code-block:: python
+
+    from sheetfu import SpreadsheetApp
+
+    sa = SpreadsheetApp('path/to/secret.json')
+    spreadsheet = sa.open_by_id('<insert spreadsheet id here>')
+    sheet = spreadsheet.get_sheet_by_name('Sheet1')
+
+    # Assuming the cells are in DATE or DATE_TIME format.
+    cells_with_dates = sheet.get_range_from_a1("A1:A2"))
+
+    print(cells_with_dates.get_values())
+    #   [
+    #       [datetime.datetime(2021, 11, 26, 16, 58, 37, 737940)],
+    #       [datetime.datetime(2021, 11, 26, 16, 58, 37, 737940)]
+    #   ]
+
+This means we can introduce python datetime operation in our code very
+effectively.
+
+
+.. code-block:: python
+
+    from sheetfu import SpreadsheetApp
+    from datetime import datetime
+
+    sa = SpreadsheetApp('path/to/secret.json')
+    spreadsheet = sa.open_by_id('<insert spreadsheet id here>')
+    sheet = spreadsheet.get_sheet_by_name('Sheet1')
+
+    a1 = sheet.get_range_from_a1("A1")
+
+    # The following will set today's date in the
+    #cell in the right google sheet format
+    a1.set_value(datetime.today())
+
+
 Contributing
 ------------