code: def install_package_requirements(self, psrc, stream_output=None):
          
          package = self.target + '/' + psrc
          assert isdir(package), package
          reqname = '/requirements.txt'
          if not exists(package + reqname):
              reqname = '/pip-requirements.txt'
              if not exists(package + reqname):
                  return
          return self.user_run_script(
              script=scripts.get_script_path('install_reqs.sh'),
              args=['/project/' + psrc + reqname],
              rw_venv=True,
              rw_project=True,
              stream_output=stream_output
              )
docs: Install from requirements.txt file found in psrc
  
          :param psrc: name of directory in environment directory