[closed] biblatex 3.3 und eigener Zitierstil

\DeclareNameFormat{labelname:poss}{% Based on labelname from biblatex.def
  \ifcase\value{uniquename}%
    \usebibmacro{name:last}
        {\namepartfamily}
    {\namepartgiven}
    {\namepartprefix}
    {\namepartsuffix}%
  \or
    \ifuseprefix
      {\usebibmacro{name:first-last}
        {\namepartfamily}
    {\namepartgiveni}
    {\namepartprefix}
    {\namepartsuffixi}}
      {\usebibmacro{name:first-last}
        {\namepartfamily}
    {\namepartgiveni}
    {\namepartprefixi}
    {\namepartsuffixi}}%
  \or
    \usebibmacro{name:first-last}
        {\namepartfamily}
    {\namepartfamily}
    {\namepartprefix}
    {\namepartsuffix}%
  \fi
  \usebibmacro{name:andothers}%
  \ifnumequal{\value{listcount}}{\value{liststop}}{'s}{}}

\DeclareFieldFormat{shorthand:poss}{%
  \ifnameundef{labelname}{\namepartfamily's}{\namepartfamily}}

\DeclareFieldFormat{citetitle:poss}{\mkbibemph{\namepartfamily}'s}

\DeclareFieldFormat{label:poss}{\namepartfamily's}

\newrobustcmd*{\posscitealias}{%
  \AtNextCite{%
    \DeclareNameAlias{labelname}{labelname:poss}%
    \DeclareFieldAlias{shorthand}{shorthand:poss}%
    \DeclareFieldAlias{citetitle}{citetitle:poss}%
    \DeclareFieldAlias{label}{label:poss}}}

\newrobustcmd*{\posscite}{%
  \posscitealias%
  \textcite}

\newrobustcmd*{\Posscite}{\bibsentence\posscite}

\newrobustcmd*{\posscites}{%
  \posscitealias%
  \textcites}