auto_fill_column.py

def auto_fill_column(rows, column_name):
    """
    Take a column name (for exm: 'Title')
    and list of columns that follows this pattern:
         Title            Actor               ...
         The Huge Wave    John Doe            ...
                          Alice Doe           ...
                          Karl Muller         ...
         Titanic          Leonardo Di Caprio  ...
                          John Doe            ...

    And fills it up in-place (the original list gets modified), like this:
         Title            Actor               ...
         The Huge Wave    John Doe            ...
         The Huge Wave    Alice Doe           ...
         The Huge Wave    Karl Muller         ...
         Titanic          Leonardo Di Caprio  ...
         Titanic          John Doe            ...

    Precondition: first row is not "" nor None
    :param rows: list of rows in the csv file
    :param column_name: string indicating the name of the field to update
    :return: None,
    """
    for row in rows:
        if row[column_name] in ["", None]:
            row[column_name] = last[column_name]
        last = row