Poisson equation with neumann bc

General
1

I am trying to solve the following version of the Poisson equation, and am unclear on expressing the 2nd Neumann bc in the equations below.

\nabla \cdot \nabla u = 0 in \Omega
\nabla u \cdot \vec{n} = 0 on \Gamma_1 \in \partial \Omega
\nabla u \cdot \vec{n} = -0.2u on \Gamma_2 \in \partial \Omega

2

See for instance: Setting multiple Dirichlet, Neumann, and Robin conditions — FEniCSx tutorial

3

@garth can @dokken 's tutorial have a link at https://fenicsproject.org/documentation/? It’s useful and helps fill gaps left by dated tutorials.

4

It does under Contributed tutorials

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