title: Why am I receiving this error when trying to install pyquery python module?
body: <p>I'm using the following command </p>
  
  <p><code>!pip install pyquery</code> </p>
  
  <p>I'm able to install other modules.  Does anyone know why this is happening? Thanks!</p>
  
  <hr>
  
  <pre><code>src/lxml/includes/etree_defs.h:14:10: fatal error: 'libxml/xmlversion.h' file not found
  #include "libxml/xmlversion.h"
           ^
  1 error generated.
  Compile failed: command 'cc' failed with exit status 1
  creating var
  creating var/folders
  creating var/folders/p1
  creating var/folders/p1/xg17tts541n1__p_srg1n2j80000gn
  creating var/folders/p1/xg17tts541n1__p_srg1n2j80000gn/T
  cc -I/usr/include/libxml2 -I/usr/include/libxml2 -c /var/folders/p1/xg17tts541n1__p_srg1n2j80000gn/T/xmlXPathInit9XZ4sL.c -o var/folders/p1/xg17tts541n1__p_srg1n2j80000gn/T/xmlXPathInit9XZ4sL.o
  /var/folders/p1/xg17tts541n1__p_srg1n2j80000gn/T/xmlXPathInit9XZ4sL.c:1:10: fatal error: 'libxml/xpath.h' file not found
  #include "libxml/xpath.h"
           ^
  1 error generated.
  *********************************************************************************
  Could not find function xmlCheckVersion in library libxml2. Is libxml2 installed?
  Perhaps try: xcode-select --install
  *********************************************************************************
  error: command 'cc' failed with exit status 1
  
  ----------------------------------------
  </code></pre>
  
  <p>Command "/usr/bin/python -c "import setuptools, tokenize;<strong>file</strong>='/private/var/folders/p1/xg17tts541n1__p_srg1n2j80000gn/T/pip-build-nn9QXj/lxml/setup.py';exec(compile(getattr(tokenize, 'open', open)(<strong>file</strong>).read().replace('\r\n', '\n'), <strong>file</strong>, 'exec'))" install --record /var/folders/p1/xg17tts541n1__p_srg1n2j80000gn/T/pip-X97yGE-record/install-record.txt --single-version-externally-managed --compile" failed with error code 1 in /private/var/folders/p1/xg17tts541n1__p_srg1n2j80000gn/T/pip-build-nn9QXj/lxml</p>