Failed building wheel for psutil on macOS

Problem

I am trying to install psutil using pip so I ran pip install psutil but I receive the following error message:

Failed building wheel for psutil
Running setup.py clean for psutil

It seems like the problem is occurring during setup.py: Building wheel for psutil (setup.py) ... error.

I have tried running :

xcode-select --install

but I get the following error message:

xcode-select: error: command line tools are already installed, use "Software Update" to install updates

I have also tried:

sudo xcode-select --switch /Library/Developer/CommandLineTools

and

sudo rm -rf /Library/Developer/CommandLineTools
xcode-select --install

Both work fine but even after restarting the terminal, I see no change.

And finally, I have tried running:

sudo xcode-select --reset

Which also makes no difference.

Solution

I just typed:

sudo open /Library/Developer/CommandLineTools/SDKs

into my terminal and it turns out that I have 2 versions of the Command Line SDK installed so it looked like this:

MacOSX.sdk -> MacOSX10.15.sdk
MacOSX10.15.sdk
MacOSX10.14.sdk

I then just deleted the older MacOSX10.14.sdk and everything starting working correctly.