Basic functions not being seen I am getting the following error when invoking "commerce_cart_order_product_line_item_delete()" in a custom module I'm writing.


  Fatal error: Call to undefined function commerce_entity_reference_delete() in
  /Users/[username]/Documents/Sites/[site_name]/profiles/commerce_kickstart/modules/contrib/commerce/modules/cart/commerce_cart.module
  on line 1268


The commerce_entity_reference_delete() function that Drupal claims it can't find resides in:


  /[site]/profiles/commerce_kickstart/modules/contrib/commerce/commerce.module


Which, if I understand correctly is THE main commerce module that makes the whole shopping cart functionality work. So, my commerce module is enabled (because my shopping cart is working, and which is confirmed also on the Modules page), so why isn't commerce.module serving up the function above for me?

Aren't I allowed to call commerce_cart_order_product_line_item_delete() from a custom module?
This function commerce_cart_order_product_line_item_delete is in commerce_cart.module in line 1259 tnen in line 1268 call commerce_entity_reference_delete, function should be in commerce.module file line 124, check the function exist there.
This is some strange if the function exist in commerce.module and return fatal error,
I suggest first be sure that the function exist in code then  clear cache and then try again.
It is allowable call any function in any custom module and drupal not have restriction about this subject.