docs: def get(self, fallback=not_set):
          """
          Returns config value.
  
          See Also:
              :meth:`.set` and :attr:`.value`
          """
  
          envvar_value = self._get_envvar_value()
          if envvar_value is not not_set:
              return envvar_value
  
          if self.has_value:
              if self._value is not not_set:
                  return self._value
              else:
                  return copy.deepcopy(self.default)
          elif fallback is not not_set:
              return fallback
          elif self.required:
              raise RequiredValueMissing(name=self.name, item=self)
          return fallback