ERROR: Failed building wheel for lxml

Please I'm not a computer guy or anything am just trying to install a script by typing :

pip install -r requirements.txt 

and then this error shows up twice during the process and I have no idea why :

First :

      Compile failed: command '/usr/bin/x86_64-linux-gnu-gcc' failed with exit code 1
      creating tmp
      cc -I/usr/include/libxml2 -I/usr/include/libxml2 -c /tmp/xmlXPathInitd5e8a29v.c -o tmp/xmlXPathInitd5e8a29v.o
      cc tmp/xmlXPathInitd5e8a29v.o -lxml2 -o a.out
      error: command '/usr/bin/x86_64-linux-gnu-gcc' failed with exit code 1
      [end of output]

  note: This error originates from a subprocess, and is likely not a problem with pip.
  ERROR: Failed building wheel for lxml
  Running setup.py clean for lxml
Failed to build lxml
Installing collected packages: lxml, chardet, alabaster, urllib3, sphinxcontrib-serializinghtml, Pygments, pockets, imagesize, idna, docutils, beautifulsoup4, sphinxcontrib-websupport, sphinxcontrib-napoleon, requests, sphinx, nyawc
  Attempting uninstall: lxml
    Found existing installation: lxml 4.9.1
    Not uninstalling lxml at /usr/lib/python3/dist-packages, outside environment /usr
    Can't uninstall 'lxml'. No files were found to uninstall.
  Running setup.py install for lxml ... error
  error: subprocess-exited-with-error

  × Running setup.py install for lxml did not run successfully.
  │ exit code: 1

and this one at the end :

 Compile failed: command '/usr/bin/x86_64-linux-gnu-gcc' failed with exit code 1
      cc -I/usr/include/libxml2 -I/usr/include/libxml2 -c /tmp/xmlXPathInitu8wuxket.c -o tmp/xmlXPathInitu8wuxket.o
      cc tmp/xmlXPathInitu8wuxket.o -lxml2 -o a.out
      error: command '/usr/bin/x86_64-linux-gnu-gcc' failed with exit code 1
      [end of output]

  note: This error originates from a subprocess, and is likely not a problem with pip.
  ERROR: Can't roll back lxml; was not uninstalled
error: legacy-install-failure

× Encountered error while trying to install package.
╰─> lxml

note: This is an issue with the package mentioned above, not pip.
hint: See above for output from the failure.

I assume it's something about the compiler gcc or something because I have lxml installed.

I'll appreciate the help and thank you so much in advance.