TypeRepresentation:a.pythonTypeRepresentation
  PyFunctionTypeRepresentation
    PsiElement(Py:DEF_KEYWORD)('def')
    PsiWhiteSpace(' ')
    PyReferenceExpression: test
      PsiElement(Py:IDENTIFIER)('test')
      PsiElement(Py:DOT)('.')
      PsiElement(Py:IDENTIFIER)('f')
    PyParameterListRepresentation
      PsiElement(Py:LPAR)('(')
      PyNamedParameterTypeRepresentation('callback')
        PsiElement(Py:IDENTIFIER)('callback')
        PsiElement(Py:COLON)(':')
        PsiWhiteSpace(' ')
        PyFunctionTypeRepresentation
          PyParameterListRepresentation
            PsiElement(Py:LPAR)('(')
            PyReferenceExpression: int
              PsiElement(Py:IDENTIFIER)('int')
            PsiElement(Py:RPAR)(')')
          PsiWhiteSpace(' ')
          PsiElement(Py:RARROW)('->')
          PsiWhiteSpace(' ')
          PyReferenceExpression: str
            PsiElement(Py:IDENTIFIER)('str')
      PsiElement(Py:RPAR)(')')
    PsiWhiteSpace(' ')
    PsiElement(Py:RARROW)('->')
    PsiWhiteSpace(' ')
    PyNoneLiteralExpression
      PsiElement(Py:NONE_KEYWORD)('None')