documentclass[border={10pt 10pt 10pt 10pt}]{standalone}

usepackage[dvipsnames]{xcolor}

usepackage{listings}

% Python style for highlighting
newcommandlatexstyle{lstset{
  language=TeX,
  basicstyle=scriptsizettfamily,
  mathescape=true,
  keywordstyle=color{MidnightBlue}bfseries,
  morekeywords={begin, addplot, addlegendentry, documentclass, usepackage, usetikzlibrary, usepgfplotslibrary, pgfplotsset, nextlist, coordinate small, draw},
}}

% Python environment
lstnewenvironment{latex}[1][mathescape]
{
latexstyle
lstset{#1}
}
{}

begin{document}

begin{latex}
 begin{tikzpicture}
  begin{loglogaxis}

addplot+ [ultra thick, dotted] table[]{
  10  0.2
  100  0.1
  1000  0.05}
coordinate [pos=0.15] (A)
coordinate [pos=0.25] (B);
addlegendentry{legend 1}
coordinate (A') at ($(A)!3pt!90:(B)$);
coordinate (B') at ($(B)!3pt!270:(A)$);
draw (A')-|(B') node[pos=0.25,above]{$1$}
  node[pos=0.75,right]{$alpha$};
draw [shorten <=-3pt,shorten >=-3pt] (A') -- (B');

  end{loglogaxis}
end{tikzpicture}
end{latex}

end{document}