'!env_var Code error in HA

Configuration
1

Hello every time I uses the ‘!env_var’ i get this code ERROR Code can some one help you please , thank you in advance

ERROR:

could not determine a constructor for the tag '!env_var’
** in “”, line 3, column 13:**
** latitude: !env_var HOME_LATITUDE**

homeassistant:
  name: KDHOME
  latitude: !env_var HOME_LATITUDE
  longitude: !env_var HOME_LONGITUDE
  elevation: 994
  unit_system: imperial
  time_zone: America/New_York
  
  #customize: !include customize.yaml

http:
  # Uncomment this to add a password (recommended!)
  api_password: !env_var HA_PASSWORD
  server_port: 8123

##############
# COMPONENTS #
##############

zwave:
  #usb_path: /dev/ttyACM0
  usb_path: /dev/zwave
  config_path: /srv/hass/hass_venv/lib/python3.4/site-packages/libopenzwave-0.3.1-py3.4-linux-armv7l.egg/config

climate:
  platform: nest
nest:
  username: !env_var NEST_EMAIL
  password: !env_var NEST_PASSWORD

mqtt:
  broker: 192.168.1.22
  port: 1883
  client_id: home-assistant-1
  username: !env_var MQTT_USERNAME
  password: !env_var MQTT_PASSWORD
     
#########
# ZONES #
#########

# Weather Prediction
sensor:
  #platform: yr
  
#########
# ZONES #
#########

zone 1:
  name: Home
  latitude: !env_var HOME_LATITUDE
  longitude: !env_var HOME_LONGITUDE
  radius: 300
  icon: mdi:home

zone 2:
  name: Mr_Parao Work
  latitude: !env_var Mr_Parao_WORK_LATITUDE
  longitude: !env_var Mr_Parao_WORK_LONGITUDE
  radius: 300
  icon: mdi:briefcase

############
# INCLUDES #
############
#group: !include_dir_merge_named includes/groups
#sensor: !include_dir_merge_list includes/sensorsdevice_tracker: !include includes/device_trackers.yaml
#media_player: !include includes/media_players.yaml
#scene: !include includes/scenes.yaml
#notify: !include includes/notify.yaml
#script: !include_dir_named includes/scripts
#automation: !include_dir_merge_list includes/automation
#input_boolean: !include includes/input_boolean.yaml
#camera: !include includes/cameras.yamldiscovery:
frontend:
history:
logbook:
sun:
#introduction:
#conversation:
#updater:
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