Can`t install python3-dev , numpy

When I install the python3-dev with the command"sudo apt-get install python3-dev",it returns:
“The following packages have unmet dependencies:
python3-dev : Depends: dh-python but it is not installable
E: Unable to correct problems, you have held broken packages.”
But the package ‘dh-python’ has no installation candidate.

When I install numpy with the command""sudo pip3 instll -U numpy, it returns:

Traceback (most recent call last):
  File "/usr/bin/pip3", line 9, in <module>
    from pip import main
ImportError: cannot import name 'main'

Any help will be appreciated.

have a look here https://devtalk.nvidia.com/default/topic/1049071/jetson-nano/pytorch-for-jetson-nano/

search for “note on upgrading pip” for the solution for your problem

Thanks, I can install the pip3 successed.
But I must add sudo when install some wheels like tf,
And I cannot install python3-dev with the error:
python3-dev : Depends: dh-python but it is not installable
E: Unable to correct problems, you have held broken packages.

I’ve just answered your subsequent repost @ https://devtalk.nvidia.com/default/topic/1052499/jetson-nano/can-t-install-python3-dev-/

HTH,
Simon