class_docstr: Raised when input data cannot be merged into a variable font.
code: def details(self):
      if "expected" in self.cause and "got" in self.cause:
          offender_index, offender = self.offender
          got = self.cause["got"][offender_index]
          return f"Expected to see {self.stack[0]}=={self.cause['expected']!r}, instead saw {got!r}\n"
      return ""
  
imports: import textwrap
label_desc: Use image node_id 5 for calling the VarLibMergeError obj's underlying member method code with example usage: obj.details() and returns: str, str, self, str, self, str, got, str