def is_tachy(age, hr):
    """
    Determines if a patient is tachycardic or not based on age
    and a heart rate measurement

    Args:
        age: patient's age
        hr: heart rate recording of interest

    Returns:
        str: 'Tachydardic' or 'Non-Tachycardic' signifying the patient's
        tachycardia state

    """
    tachy = False
    if age < 1:
        return'Patient is too young to detect tachycardia ' \
              'with this program. Patient must be at least 1YO'
    elif age >= 1 and age <= 2 and hr >= 151:
        tachy = True
    elif age >= 3 and age <= 4 and hr >= 137:
        tachy = True
    elif age >= 5 and age <= 7 and hr >= 133:
        tachy = True
    elif age > 8 and age <= 11 and hr >= 130:
        tachy = True
    elif age >= 12 and age <= 15 and hr >= 119:
        tachy = True
    elif age >= 15 and hr >= 100:
        tachy = True
    if tachy:
        return 'Tachycardic'
    else:
        return 'Non-Tachycardic'