code: def pathname_configs(
      url_base_pathname=None,
      routes_pathname_prefix=None,
      requests_pathname_prefix=None,
  ):
      _pathname_config_error_message = """
      {} This is ambiguous.
      To fix this, set `routes_pathname_prefix` instead of `url_base_pathname`.
  
      Note that `requests_pathname_prefix` is the prefix for the AJAX calls that
      originate from the client (the web browser) and `routes_pathname_prefix` is
      the prefix for the API routes on the backend (this flask server).
      `url_base_pathname` will set `requests_pathname_prefix` and
      `routes_pathname_prefix` to the same value.
      If you need these to be different values then you should set
      `requests_pathname_prefix` and `routes_pathname_prefix`,
      not `url_base_pathname`.
      """
      url_base_pathname = get_combined_config(
          "url_base_pathname", url_base_pathname
      )
  
      routes_pathname_prefix = get_combined_config(
          "routes_pathname_prefix", routes_pathname_prefix
      )
  
      requests_pathname_prefix = get_combined_config(
          "requests_pathname_prefix", requests_pathname_prefix
      )
  
      if (
          url_base_pathname is not None
          and requests_pathname_prefix is not None
      ):
          raise exceptions.InvalidConfig(
              _pathname_config_error_message.format(
                  "You supplied `url_base_pathname` and `requests_pathname_prefix`."
              )
          )
  
      if (
          url_base_pathname is not None
          and routes_pathname_prefix is not None
      ):
          raise exceptions.InvalidConfig(
              _pathname_config_error_message.format(
                  "You supplied `url_base_pathname` and `routes_pathname_prefix`."
              )
          )
  
      if (
          url_base_pathname is not None
          and routes_pathname_prefix is None
      ):
          routes_pathname_prefix = url_base_pathname
      elif routes_pathname_prefix is None:
          routes_pathname_prefix = "/"
  
      if not routes_pathname_prefix.startswith("/"):
          raise exceptions.InvalidConfig(
              "`routes_pathname_prefix` needs to start with `/`"
          )
      if not routes_pathname_prefix.endswith("/"):
          raise exceptions.InvalidConfig(
              "`routes_pathname_prefix` needs to end with `/`"
          )
  
      app_name = load_dash_env_vars().DASH_APP_NAME
  
      if not requests_pathname_prefix and app_name:
          requests_pathname_prefix = (
              "/" + app_name + routes_pathname_prefix
          )
      elif requests_pathname_prefix is None:
          requests_pathname_prefix = routes_pathname_prefix
  
      if not requests_pathname_prefix.startswith("/"):
          raise exceptions.InvalidConfig(
              "`requests_pathname_prefix` needs to start with `/`"
          )
  
      return (
          url_base_pathname,
          routes_pathname_prefix,
          requests_pathname_prefix,
      )
  
file_path: dash/dash/_configs.py
imports: import os
  import flask
  from .None import exceptions
  from ._utils import AttributeDict
label_desc: Use image node_id 3 for calling a global function with example usage: pathname_configs(url_base_pathname, routes_pathname_prefix, requests_pathname_prefix) and returns: url_base_pathname,  routes_pathname_prefix,  requests_pathname_prefix