DEPRECATION: Python 2.7 will reach the end of its life on January 1st, 2020. Please upgrade your Python as Python 2.7 won't be maintained after that date. A future version of pip will drop support for Python 2.7. More details about Python 2 support in pip, can be found at https://pip.pypa.io/en/latest/development/release-process/#python-2-support
The command '/bin/sh -c echo "deb http://cran.rstudio.com/bin/linux/ubuntu xenial/" > /etc/apt/sources.list.d/R.list     && apt-key adv --keyserver keyserver.ubuntu.com --recv E084DAB9     && apt-get -q -q update     && apt-get -y install --no-install-recommends r-base-core r-base-dev     && rm -rf /var/lib/apt/lists/*     && Rscript --vanilla -e "install.packages('jsonlite', repos='http://cran.rstudio.com/'); print(system.file(package = 'jsonlite')); q(status=as.integer(system.file(package = 'jsonlite') == ''))"' returned a non-zero code: 100