Parse cell till its end and set content, lines_to_next_cell.
        Return the position of next cell start

def find_cell_content(self, lines):
        """Parse cell till its end and set content, lines_to_next_cell.
        Return the position of next cell start"""
        cell_end_marker, next_cell_start, explicit_eoc = self.find_cell_end(lines)

        # Metadata to dict
        if self.start_code_re.match(lines[0]) or self.alternative_start_code_re.match(lines[0]):
            cell_start = 1
        else:
            cell_start = 0

        # Cell content
        source = lines[cell_start:cell_end_marker]
        self.org_content = [line for line in source]

        if self.cell_type != 'code' or (self.metadata and not is_active('py', self.metadata)) \
                or (self.language is not None and self.language != self.default_language):
            source = uncomment(source, self.comment)
        elif self.metadata is not None and self.comment_magics:
            source = self.uncomment_code_and_magics(source)

        self.content = source

        self.lines_to_next_cell = count_lines_to_next_cell(
            cell_end_marker,
            next_cell_start,
            len(lines),
            explicit_eoc)

        return next_cell_start