Create a new cell magic in Jupyter (and Colab)

new_magic.py

from IPython.display import HTML
from IPython.core.magic import register_cell_magic

# equivalent to %%js
@register_cell_magic
def myjs(line, cell):
  return HTML(f'''
  <script>
  {cell}
  </script>
  ''')

# assign cell content to a variable too
@register_cell_magic
def var(line, cell):
  name = line.split()[0]
  globals()[name] = cell
  return cell