def attack_multiplier(attacker_type, defender_type):
    """
    Attack Multiplier Chart:
        - Water -> Fire (Damage x2.5)
        - Electric -> Water (Damage x1.3)
        - Ground -> Electric (Damage x2)
        - Fire -> Grass (Damage x3)
        - Grass -> Water (Damage x1.5)

    Using the Attack Multiplier Chart above, return the multipliers
    for each attack-defense combination. For example, when
    Attacker type is Water AND Defender type is Fire,
    your function should return 2.5

    For all other attacker-defender combinations, which are not
    given in the Attack Multiplier Chart, your function should
    return 1.0.

    :param attacker_type: This parameter is a string that indicates the
                          type of the attacker.
    :param defender_type: This parameter is a string that indicates the
                          type of the defender.
    :return             : This function will return a float value, which
                          represents the attack multiplier for given
                          combination.

    Task Objectives:
    1. Using if conditions for decision making
    2. Combining several condition statements into one
    """
    ##### Pseudocode #####
    # 1. If Attacker is Water and Defender is Fire, return 2.5
    # 2. Else if Attacker is Electric and Defender is Water, return 1.3
    # 3. Else if Attacker is Ground and Defender is Electric, return 2.0
    # 4. Else if Attacker is Fire and Defender is Grass, return 3.0
    # 5. Else if Attacker is Grass and Defender is Water, return 1.5
    # 6. Else, return 1.0
    ######################
    
    if attacker_type.lower() == 'water' and defender_type.lower() == 'fire':
        return 2.5
    elif attacker_type.lower() == 'electric' and defender_type.lower() == 'water':
        return 1.3
    elif attacker_type.lower() == 'ground' and defender_type.lower() == 'electric':
        return 2
    elif attacker_type.lower() == 'fire' and defender_type.lower() == 'grass':
        return 3
    elif attacker_type.lower() == 'grass' and defender_type.lower() == 'water':
        return 1.5
    else:
        return 1.0