how to use DbContextScope with Parallel.ForEach

[pentest30]

how i can use DbContextScope with Paralle.Foreach
because i was not able to use it correctly . and this exception thrown every time.
"The context cannot be used while the model is being created. This exception may be thrown if the context is used inside the OnModelCreating method or if the same context instance is accessed by multiple threads concurrently. Note that instance members of DbContext and related classes are not guaranteed to be thread safe."