parameters: (self, token)
docstring: Resolve command prefix from the prefix itself or its alias.
  
      Args:
        token: a str to be resolved.
  
      Returns:
        If resolvable, the resolved command prefix.
        If not resolvable, None.
docstring_summary: Resolve command prefix from the prefix itself or its alias.
docstring_tokens: Resolve command prefix from the prefix itself or its alias .
function: def _resolve_prefix(self, token):
      """Resolve command prefix from the prefix itself or its alias.
  
      Args:
        token: a str to be resolved.
  
      Returns:
        If resolvable, the resolved command prefix.
        If not resolvable, None.
      """
      if token in self._handlers:
        return token
      elif token in self._alias_to_prefix:
        return self._alias_to_prefix[token]
      else:
        return None
function_tokens: def _resolve_prefix ( self , token ) : if token in self . _handlers : return token elif token in self . _alias_to_prefix : return self . _alias_to_prefix [ token ] else : return None