docs: def to_string(
          self,
          fmt: str = "medium",
          canonicalize: bool = False,
          decanonicalize: bool = False,
          orthologize: str = None,
      ) -> str:
          """Convert AST object to string
  
          Args:
              fmt (str): short, medium, long formatted BEL statements
                  short = short function and short relation format
                  medium = short function and long relation format
                  long = long function and long relation format
  
          Returns:
              str: string version of BEL AST
          """
  
          arg_string = ", ".join([a.to_string(fmt=fmt) for a in self.args])
  
          if fmt in ["short", "medium"]:
              function_name = self.name_short
          else:
              function_name = self.name
  
          return "{}({})".format(function_name, arg_string)