<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
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<USER_TASK:>
Description:
 def validate_params(valid_options, params):
 """ Helps us validate the parameters for the request :param valid_options: a list of strings of valid options for the api request :param params: a dict, the key-value store which we really only care about the key which has tells us what the user is using for the API request :returns: None or throws an exception if the validation fails """

    #crazy little if statement hanging by himself :(
    if not params:
        return

    #We only allow one version of the data parameter to be passed
    data_filter = ['data', 'source', 'external_url', 'embed']
    multiple_data = [key for key in params.keys() if key in data_filter]
    if len(multiple_data) > 1:
        raise Exception("You can't mix and match data parameters")

    #No bad fields which are not in valid options can pass
    disallowed_fields = [key for key in params.keys() if key not in valid_options]
    if disallowed_fields:
        field_strings = ",".join(disallowed_fields)
        raise Exception("{} are not allowed fields".format(field_strings))