TikZ UML diagram special character problem

I'm trying to create an UML diagram using TikZ and pgf-umlcd, unfortunately I seem to have some kind of special character problem and was not able to figure out how to escape them right, an example would be:

\begin{tikzpicture}
\begin{package}{Test}
\begin{interface}[text width=7cm]{TestInterface}{0,0}
\operation{testOperation(a : Map<String, Integer>>) : Boolean}
\end{interface}
\end{package}
\end{tikzpicture}


Unfortunately the greater than and less than characters are not printed in a PDF file like they should be instead some "character mess" is printed. What's wrong?

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Just add \usepackage[T1]{fontenc} for direct support of the < and > character. To avoid a >> ligature, you youd insert {}:

\documentclass{article}
\usepackage[T1]{fontenc}
\usepackage{tikz}
\usepackage{pgf-umlcd}
\begin{document}
\begin{tikzpicture}
\begin{package}{Test}
\begin{interface}[text width=7cm]{TestInterface}{0,0}
\operation{testOperation(a : Map<String, Integer>{}>) : Boolean}
\end{interface}
\end{package}
\end{tikzpicture}
\end{document}

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