TypeRepresentation:a.pythonTypeRepresentation
  PyElement
    PsiElement(Py:AT)('@')
    PsiElement(Py:IDENTIFIER)('Todo')
    PsiElement(Py:LPAR)('(')
    PsiElement(Py:TICK)('`')
    PsiElement(Py:IDENTIFIER)('Unpack')
    PsiElement(Py:LBRACKET)('[')
    PsiElement(Py:RBRACKET)(']')
    PsiElement(Py:TICK)('`')
    PsiWhiteSpace(' ')
    PsiElement(Py:IDENTIFIER)('special')
    PsiWhiteSpace(' ')
    PsiElement(Py:IDENTIFIER)('form')
    PsiElement(Py:RPAR)(')')