code: def str_signature(sig):
      """String representation of type signature
  
      >>> from sympy.multipledispatch.dispatcher import str_signature
      >>> str_signature((int, float))
      'int, float'
      """
      return ", ".join(cls.__name__ for cls in sig)
  
imports: from __future__ import annotations
  from warnings import warn
  import inspect
  from .conflict import ordering, ambiguities, super_signature, AmbiguityWarning
  from .utils import expand_tuples
  import itertools
label_desc: Use image node_id 6 for calling a global function with example usage: str_signature(sig) and returns: str