The real power of programming in languages like Python and R is not in the language itself but rather in ability to use tens of thousands of publicly available libraries. The Python Package Index for example lists over 67000 packages for Python programmers to use. Similarly, CRAN package repository features over 7300 packages for R programmers to use.
Python
To add package to a Python notebook type the following in to the Python Notebook cell:
!pip install PACKAGE_NAME
R
To add a package to a R notebook, type the following in to the R Notebook cell:
install.packages("PACKAGE_NAME")
Scala
Scala notebooks currently don't support installing additional libraries.