How to use the pdfplumber.utils.extract_text function in pdfplumber

def extract_text(self,
        x_tolerance=utils.DEFAULT_X_TOLERANCE,
        y_tolerance=utils.DEFAULT_Y_TOLERANCE):

        return utils.extract_text(self.chars,
            x_tolerance=x_tolerance,
            y_tolerance=y_tolerance)

)

        for row in self.rows:
            arr = []
            row_chars = [ char for char in chars
                if char_in_bbox(char, row.bbox) ]

            for cell in row.cells:
                if cell == None:
                    cell_text = None
                else:
                    cell_chars = [ char for char in row_chars
                        if char_in_bbox(char, cell) ]

                    if len(cell_chars):
                        cell_text = utils.extract_text(cell_chars,
                            x_tolerance=x_tolerance,
                            y_tolerance=y_tolerance).strip()
                    else:
                        cell_text = ""
                arr.append(cell_text)
            table_arr.append(arr)

        return table_arr