code: def parse_unary_op(v: ast.UnaryOp):
      operand = parse_expr(v.operand)
  
      assert isinstance(operand, (float, int))
      assert isinstance(v.op, ast.USub)
  
      return -operand
  
file_path: gluonts/src/gluonts/core/serde/_parse.py
imports: import ast
  from functools import singledispatch
label_desc: Use image node_id 3 for calling a global function with example usage: parse_unary_op(v) and returns: unknown