def extract_cells(raw_txt):
    """Manually extract cells in potential broken json `raw_txt`"""
    lines = raw_txt.split('\n')
    cells = []
    i = 0
    while not lines[i].startswith(' "cells"'):
        i += 1
    i += 1
    start = '\n'.join(lines[:i])
    while lines[i] != ' ],':
        while lines[i] != '  {':
            i += 1
        j = i
        while not lines[j].startswith('  }'):
            j += 1
        c = '\n'.join(lines[i:j + 1])
        if not c.endswith(','):
            c = c + ','
        cells.append(c)
        i = j + 1
    end = '\n'.join(lines[i:])
    return start, cells, end
