HTTP REQUEST

    GET https://api.nasa.gov/planetary/apod

    QUERY PARAMETERS

    Parameter	Type	Default	Description
    date	YYYY-MM-DD	today	The date of the APOD image to retrieve
    concept_tags	bool	False	Return an ordered dictionary of concepts from the APOD explanation
    api_key	string	DEMO_KEY	api.nasa.gov key for expanded usage
    EXAMPLE QUERY

    https://api.nasa.gov/planetary/apod?concept_tags=True&api_key=DEMO_KEY

def apod(date=None, concept_tags=None):
    '''
    HTTP REQUEST

    GET https://api.nasa.gov/planetary/apod

    QUERY PARAMETERS

    Parameter	Type	Default	Description
    date	YYYY-MM-DD	today	The date of the APOD image to retrieve
    concept_tags	bool	False	Return an ordered dictionary of concepts from the APOD explanation
    api_key	string	DEMO_KEY	api.nasa.gov key for expanded usage
    EXAMPLE QUERY

    https://api.nasa.gov/planetary/apod?concept_tags=True&api_key=DEMO_KEY
    '''
    base_url = "https://api.nasa.gov/planetary/apod?"

    if date:
        try:
            vali_date(date)
            base_url += "date=" + date + "&"
        except:
            raise ValueError("Incorrect date format, should be YYYY-MM-DD")
    if concept_tags == True:
        base_url += "concept_tags=True" + "&"

    req_url = base_url + "api_key=" + nasa_api_key()

    return dispatch_http_get(req_url)