def delete_previous(self):
        """Delete char before cursor.

        If we use it when there is a character before
        the cursor, the character is deleted.

        If there's no character before the cursor, then
        nothing happens.
        """
        ### if self.col equals 0, there's no character
        ### before the cursor to delete, so we can leave
        ### the method right away
        if self.col == 0:
            return

        ### otherwise we delete the character before the
        ### cursor

        ## pop the character behind the current column
        ## from the line, referencing it
        char_obj = self.line.pop(self.col - 1)

        ## reposition the characters in the line one
        ## beside the other, so they end up occupying
        ## the space left by the removed character
        self.line.reposition_chars()

        ## since the cursor went back one column,
        ## decrement the current column by one unit
        self.col += -1

        ### we then reposition cursor so that it sits in
        ### the appropriate position according to its column
        ### number; this also update its size when suitable
        self.reposition()
Delete char before cursor.

        If we use it when there is a character before
        the cursor, the character is deleted.

        If there's no character before the cursor, then
        nothing happens.
        
nodezator/textman/entryedition/cursor.py