NASA-tutorials bug: The Colab PyDAP tutorials have a bug when pydap.client is imported

[jgallagher59701]

The PyDAP notebooks seem to need to have the cell that imports PyDAP run twice to work around an error on the line 'ifrom pydap.client import open_url'. No idea why.

See: https://colab.research.google.com/github/OPENDAP/NASA-tutorials/blob/main/tutorials/colab/3.pydap_dap4_basic.ipynb and run down to the cell that includes

from pydap.client import open_url