diff --git a/.github/workflows/run_linter.yml b/.github/workflows/run_linter.yml
index 265fdfd..28ff5cc 100644
--- a/.github/workflows/run_linter.yml
+++ b/.github/workflows/run_linter.yml
@@ -23,4 +23,4 @@ jobs:
         pip install flake8
     - name: Lint with flake8
       run: |
-        flake8 */ --count --max-complexity=10 --max-line-length=120 --statistics
\ No newline at end of file
+        flake8 */ --count --ignore=F821 --max-complexity=10 --max-line-length=120 --statistics
\ No newline at end of file
diff --git a/common/client.py b/common/client.py
index c581d17..9130797 100644
--- a/common/client.py
+++ b/common/client.py
@@ -1,6 +1,7 @@
 from sinch import SinchClient
 
 sinch_client = SinchClient(
-    application_key="YOUR_application_key",
-    application_secret="YOUR_application_secret"
+    key_id="YOUR_KEY_ID",
+    key_secret="YOUR_KEY_SECRET",
+    project_id="YOUR_PROJECT_ID"
 )
diff --git a/common/client_with_environment_variables.py b/common/client_with_environment_variables.py
index 95dd118..9348eb2 100644
--- a/common/client_with_environment_variables.py
+++ b/common/client_with_environment_variables.py
@@ -2,6 +2,7 @@
 from sinch import SinchClient
 
 sinch_client = SinchClient(
-    application_key=os.getenv("APPLICATION_KEY"),
-    application_secret=os.getenv("APPLICATION_SECRET")
+    key_id=os.getenv("KEY_ID"),
+    key_secret=os.getenv("KEY_SECRET"),
+    project_id=os.getenv("PROJECT_ID")
 )
diff --git a/common/voice_and_verification_client.py b/common/voice_and_verification_client.py
new file mode 100644
index 0000000..2ee7168
--- /dev/null
+++ b/common/voice_and_verification_client.py
@@ -0,0 +1,6 @@
+from sinch import SinchClient
+
+sinch_client = SinchClient(
+    application_key="YOUR_APPLICATION_KEY",
+    application_secret="YOUR_APPLICATION_SECRET"
+)
diff --git a/common/voice_and_verification_client_with_environment_variables.py b/common/voice_and_verification_client_with_environment_variables.py
new file mode 100644
index 0000000..95dd118
--- /dev/null
+++ b/common/voice_and_verification_client_with_environment_variables.py
@@ -0,0 +1,7 @@
+import os
+from sinch import SinchClient
+
+sinch_client = SinchClient(
+    application_key=os.getenv("APPLICATION_KEY"),
+    application_secret=os.getenv("APPLICATION_SECRET")
+)
diff --git a/numbers/rent_and_configure_a_virtual_number.py b/numbers/rent_and_configure_a_virtual_number.py
index 4721931..6e33bba 100644
--- a/numbers/rent_and_configure_a_virtual_number.py
+++ b/numbers/rent_and_configure_a_virtual_number.py
@@ -1,11 +1,3 @@
-from sinch import SinchClient
-
-sinch_client = SinchClient(
-    key_id="YOUR_key_id",
-    key_secret="YOUR_key_secret",
-    project_id="YOUR_project_id"
-)
-
 activate_number_response = sinch_client.numbers.available.activate(
     phone_number="YOUR_phone_number",
     sms_configuration={
diff --git a/numbers/rent_and_configure_a_virtual_number_using_rest.py b/numbers/rent_and_configure_a_virtual_number_using_rest.py
deleted file mode 100644
index 7e0958d..0000000
--- a/numbers/rent_and_configure_a_virtual_number_using_rest.py
+++ /dev/null
@@ -1,31 +0,0 @@
-import requests
-
-project_id = "YOUR_projectId"
-phone_number = "YOUR_phoneNumber"
-url = "https://numbers.api.sinch.com/v1/projects/" + project_id + "/availableNumbers/" + phone_number + ":rent"
-
-payload = {
-  "smsConfiguration": {
-    "servicePlanId": "YOUR_servicePlanId",
-    "scheduledProvisioning": {
-      "status": "WAITING",
-      "errorCodes": [
-        "INTERNAL_ERROR"
-      ]
-    },
-    "campaignId": "YOUR_10DLC_campaignId"
-  },
-  "voiceConfiguration": {
-    "appId": "YOUR_appId",
-    "scheduledProvisioning": {
-      "status": "WAITING"
-    }
-  }
-}
-
-headers = {"Content-Type": "application/json"}
-
-response = requests.post(url, json=payload, headers=headers, auth=('YOUR_username', 'YOUR_password'))
-
-data = response.json()
-print(data)
diff --git a/numbers/rent_any_number.py b/numbers/rent_any_number.py
index 8e8c373..a49fe43 100644
--- a/numbers/rent_any_number.py
+++ b/numbers/rent_any_number.py
@@ -1,11 +1,3 @@
-from sinch import SinchClient
-
-sinch_client = SinchClient(
-    key_id="YOUR_key_id",
-    key_secret="YOUR_key_secret",
-    project_id="YOUR_project_id"
-)
-
 activate_number_response = sinch_client.numbers.available.rent_any(
     region_code="YOUR_region_code",
     type_="YOUR_number_type",
diff --git a/numbers/search_for_a_virtual_number_using_rest.py b/numbers/search_for_a_virtual_number_using_rest.py
deleted file mode 100644
index 5ec6d86..0000000
--- a/numbers/search_for_a_virtual_number_using_rest.py
+++ /dev/null
@@ -1,13 +0,0 @@
-import requests
-
-project_id = "YOUR_projectId"
-url = "https://numbers.api.sinch.com/v1/projects/" + project_id + "/availableNumbers"
-
-query = {
-  "regionCode": "US",
-  "type": "LOCAL"
-}
-response = requests.get(url, params=query, auth=('YOUR_username', 'YOUR_password'))
-
-data = response.json()
-print(data)
diff --git a/numbers/search_for_virtual_number.py b/numbers/search_for_virtual_number.py
index bbebfbd..8d8d2bb 100644
--- a/numbers/search_for_virtual_number.py
+++ b/numbers/search_for_virtual_number.py
@@ -1,11 +1,3 @@
-from sinch import SinchClient
-
-sinch_client = SinchClient(
-    key_id="YOUR_key_id",
-    key_secret="YOUR_key_secret",
-    project_id="YOUR_project_id"
-)
-
 available_numbers_response = sinch_client.numbers.available.list(
     region_code="YOUR_region_code",
     number_type="YOUR_number_type"
diff --git a/sms/send_sms_message.py b/sms/send_sms_message.py
index da3ee3c..5d991b2 100644
--- a/sms/send_sms_message.py
+++ b/sms/send_sms_message.py
@@ -1,11 +1,3 @@
-from sinch import SinchClient
-
-sinch_client = SinchClient(
-    key_id="YOUR_key_id",
-    key_secret="YOUR_key_secret",
-    project_id="YOUR_project_id"
-)
-
 send_batch_response = sinch_client.sms.batches.send(
     body="Hello from Sinch!",
     to=["YOUR_to_number"],
diff --git a/sms/send_sms_using_rest.py b/sms/send_sms_using_rest.py
deleted file mode 100644
index 9c43fd2..0000000
--- a/sms/send_sms_using_rest.py
+++ /dev/null
@@ -1,25 +0,0 @@
-import requests
-
-service_plan_id = ""
-api_token = ""
-sinch_number = ""
-to_number = ""
-url = "https://us.sms.api.sinch.com/xms/v1/" + service_plan_id + "/batches"
-
-payload = {
-  "from": sinch_number,
-  "to": [
-    to_number
-  ],
-  "body": "Hello how are you"
-}
-
-headers = {
-  "Content-Type": "application/json",
-  "Authorization": "Bearer " + api_token
-}
-
-response = requests.post(url, json=payload, headers=headers)
-
-data = response.json()
-print(data)
diff --git a/verification/initiate_sms_verification.py b/verification/initiate_sms_verification.py
index 303822c..fd67e2c 100644
--- a/verification/initiate_sms_verification.py
+++ b/verification/initiate_sms_verification.py
@@ -1,11 +1,5 @@
-from sinch import SinchClient
 from sinch.domains.verification.models import VerificationIdentity
 
-sinch_client = SinchClient(
-    application_key="YOUR_application_key",
-    application_secret="YOUR_application_secret"
-)
-
 response = sinch_client.verification.verifications.start_sms(
     identity=VerificationIdentity(
         type="number",
diff --git a/verification/verification_domain.py b/verification/verification_domain.py
index 1c0cb5e..c999c58 100644
--- a/verification/verification_domain.py
+++ b/verification/verification_domain.py
@@ -1,9 +1,3 @@
-from sinch import SinchClient
 from sinch.domains.verification import Verification
 
-sinch_client = SinchClient(
-    application_key="YOUR_application_key",
-    application_secret="YOUR_application_secret"
-)
-
 verification_client = Verification(sinch_client)
diff --git a/voice/text_to_speech.py b/voice/text_to_speech.py
index a61bd56..b117adc 100644
--- a/voice/text_to_speech.py
+++ b/voice/text_to_speech.py
@@ -1,10 +1,3 @@
-from sinch import SinchClient
-
-sinch_client = SinchClient(
-    application_key="YOUR_application_key",
-    application_secret="YOUR_application_secret"
-)
-
 response = sinch_client.voice.callouts.text_to_speech(
     destination={
         "type": "number",
diff --git a/voice/text_to_speech_using_rest.py b/voice/text_to_speech_using_rest.py
deleted file mode 100644
index 7b818b2..0000000
--- a/voice/text_to_speech_using_rest.py
+++ /dev/null
@@ -1,28 +0,0 @@
-import requests
-
-key = ""
-secret = ""
-from_number = ""
-to = ""
-locale = ""
-url = "https://calling.api.sinch.com/calling/v1/callouts"
-
-payload = {
-  "method": "ttsCallout",
-  "ttsCallout": {
-    "cli": from_number,
-    "destination": {
-      "type": "number",
-      "endpoint": to
-    },
-    "locale": locale,
-    "text": "Hello, this is a call from Sinch. Congratulations! You made your first call."
-  }
-}
-
-headers = {"Content-Type": "application/json"}
-
-response = requests.post(url, json=payload, headers=headers, auth=(key, secret))
-
-data = response.json()
-print(data)
diff --git a/voice/voice_domain.py b/voice/voice_domain.py
index 24588fa..a4c46fd 100644
--- a/voice/voice_domain.py
+++ b/voice/voice_domain.py
@@ -1,9 +1,3 @@
-from sinch import Client
 from sinch.domains.voice import Voice
 
-sinch_client = Client(
-    application_key="YOUR_application_key",
-    application_secret="YOUR_application_secret"
-)
-
 voice_client = Voice(sinch_client)