     ...contents of test/fixtures/organization.json...
 
     iex> Closex.MockClient.update_opportunity(Closex.MockClient.not_found_id(), %{})
-    {:error, :mock_not_found}
+    {:error, "Empty query: Opportunity matching query does not exist."}
 
     iex> Closex.MockClient.update_opportunity(Closex.MockClient.not_found_id(), %{"foo" => "bar"})
-    {:error, :mock_not_found}
+    {:error, "Empty query: Opportunity matching query does not exist."}
   """
   def update_opportunity(_opportunity_id, _payload, _opts \\ [])
 
   def update_opportunity(@not_found_id, _payload, _opts) do
-    {:error, :mock_not_found}
+    {:error, "Empty query: Opportunity matching query does not exist."}
   end
 
   def update_opportunity(opportunity_id, payload, opts) do

    ...contents of test/fixtures/organization.json...

    iex> Closex.MockClient.get_organization(Closex.MockClient.not_found_id())
    {:error, :mock_not_found}
  """
  def get_organization(id, opts \\ [])

  def get_organization(id = @not_found_id, opts) do
    send(self(), {:closex_mock_client, :get_organization, [id, opts]})
    {:error, :mock_not_found}
  end

  def get_organization(id, opts) do

    ...contents of test/fixtures/organization.json...

    iex> Closex.MockClient.update_lead(Closex.MockClient.not_found_id(), %{})
    {:error, "Empty query: Lead matching query does not exist."}

    iex> Closex.MockClient.update_lead(Closex.MockClient.not_found_id(), %{"foo" => "bar"})
    {:error, "Empty query: Lead matching query does not exist."}
  """
  def update_lead(lead_id, payload, opts \\ [])

  def update_lead(@not_found_id, _payload, _opts) do
    {:error, "Empty query: Lead matching query does not exist."}
  end

  def update_lead(lead_id = @timeout_query, payload, opts) do
