"""Formats community content by appending entities and keywords to the base text.

This function takes a base text and two lists (entities and keywords) and appends a formatted
string to the base text indicating the presence of entities and keywords. If both lists are empty,
the function returns the base text unchanged. If either list contains more than three items, only
the first three are shown, followed by a count of the remaining items.

Args:
    base_text (str): The base text to which entities and keywords will be appended.
    entities (list[str]): A list of entities to be included in the formatted content.
    keywords (list[str]): A list of keywords to be included in the formatted content.

Returns:
    str: The formatted content string, which includes the base text and any appended entities
         and keywords.

Examples:
    >>> _format_community_content("Sample text", [], [])
    'Sample text'

    >>> _format_community_content("Sample text", ["entity1"], [])
    'Sample text\n  Contains:\n    Entities: entity1'

    >>> _format_community_content("Sample text", [], ["keyword1"])
    'Sample text\n  Contains:\n    Keywords: keyword1'

    >>> _format_community_content("Sample text", ["entity1", "entity2", "entity3", "entity4"], ["keyword1", "keyword2", "keyword3", "keyword4"])
    'Sample text\n  Contains:\n    Entities: entity1, entity2, entity3 and 1 more\n    Keywords: keyword1, keyword2, keyword3 and 1 more'
"""
You should write code starting with:
from typing import List

def _format_community_content(base_text: str, entities: List[str], keywords: List[str]) -> str:
    # TODO: Implement this function based on the docstring.
    pass

