old_contents: import sys
  import os
  sys.path.append(os.path.join(os.path.dirname(__file__), '..'))
  sys.path.append(os.path.join(os.path.dirname(__file__), '..', 'lib'))
  
  
  def is_valid_python_version():
      version_valid = False
  
      ver = sys.version_info
      if (2 == ver.major) and (7 <= ver.minor):
          version_valid = True
  
      if (3 == ver.major) and (4 <= ver.minor):
          version_valid = True
  
      return version_valid
  
  
  def python_short_ver_str():
      ver = sys.version_info
      return "%s.%s" % (ver.major, ver.minor)
  
  
  def are_deps_installed():
      installed = False
  
      try:
          import peewee
          import bitcoinrpc.authproxy
          import simplejson
          installed = True
      except ImportError as e:
          print("[error]: Missing dependencies")
  
      return installed
  
  
  def is_database_correctly_configured():
      import peewee
      import config
  
      configured = False
  
      cannot_connect_message = "Cannot connect to database. Please ensure database service is running and user access is properly configured in 'sentinel.conf'."
  
      try:
          db = config.db
          db.connect()
          configured = True
      except (peewee.ImproperlyConfigured, peewee.OperationalError, ImportError) as e:
          print("[error]: %s" % e)
          print(cannot_connect_message)
          sys.exit(1)
  
      return configured
  
  
  def has_dash_conf():
      import config
      import io
  
      valid_dash_conf = False
  
      # ensure dash_conf exists & readable
      #
      # if not, print a message stating that Dash Core must be installed and
      # configured, including JSONRPC access in dash.conf
      try:
          f = io.open(config.dash_conf)
          valid_dash_conf = True
      except IOError as e:
          print(e)
  
      return valid_dash_conf
  
  
  # === begin main
  
  
  def main():
      install_instructions = "\tpip install -r requirements.txt"
  
      if not is_valid_python_version():
          print("Python %s is not supported" % python_short_ver_str())
          sys.exit(1)
  
      if not are_deps_installed():
          print("Please ensure all dependencies are installed:")
          print(install_instructions)
          sys.exit(1)
  
      if not is_database_correctly_configured():
          print("Please ensure correct database configuration.")
          sys.exit(1)
  
      if not has_dash_conf():
          print("DashCore must be installed and configured, including JSONRPC access in dash.conf")
          sys.exit(1)
  
  
  main()
  
new_contents: import sys
  import os
  sys.path.append(os.path.join(os.path.dirname(__file__), '..'))
  sys.path.append(os.path.join(os.path.dirname(__file__), '..', 'lib'))
  
  
  def is_valid_python_version():
      version_valid = False
  
      ver = sys.version_info
  
      # minimum supported Python version is 3.6
      if (3 == ver.major) and (6 <= ver.minor):
          version_valid = True
  
      return version_valid
  
  
  def python_short_ver_str():
      ver = sys.version_info
      return "%s.%s" % (ver.major, ver.minor)
  
  
  def are_deps_installed():
      installed = False
  
      try:
          import peewee
          import bitcoinrpc.authproxy
          import simplejson
          installed = True
      except ImportError as e:
          print("[error]: Missing dependencies")
  
      return installed
  
  
  def is_database_correctly_configured():
      import peewee
      import config
  
      configured = False
  
      cannot_connect_message = "Cannot connect to database. Please ensure database service is running and user access is properly configured in 'sentinel.conf'."
  
      try:
          db = config.db
          db.connect()
          configured = True
      except (peewee.ImproperlyConfigured, peewee.OperationalError, ImportError) as e:
          print("[error]: %s" % e)
          print(cannot_connect_message)
          sys.exit(1)
  
      return configured
  
  
  def has_dash_conf():
      import config
      import io
  
      valid_dash_conf = False
  
      # ensure dash_conf exists & readable
      #
      # if not, print a message stating that Dash Core must be installed and
      # configured, including JSONRPC access in dash.conf
      try:
          f = io.open(config.dash_conf)
          valid_dash_conf = True
      except IOError as e:
          print(e)
  
      return valid_dash_conf
  
  
  # === begin main
  
  
  def main():
      install_instructions = "\tpip install -r requirements.txt"
  
      if not is_valid_python_version():
          print("Python %s is not supported" % python_short_ver_str())
          sys.exit(1)
  
      if not are_deps_installed():
          print("Please ensure all dependencies are installed:")
          print(install_instructions)
          sys.exit(1)
  
      if not is_database_correctly_configured():
          print("Please ensure correct database configuration.")
          sys.exit(1)
  
      if not has_dash_conf():
          print("DashCore must be installed and configured, including JSONRPC access in dash.conf")
          sys.exit(1)
  
  
  main()
  
subject: Set minimum Python version to 3.6 in code (#86)