import yaml


def get_parameter_from_yaml(parameter, yfile):
    """
    Returns the value of a given parameter in file.yaml
    parameter must be given in string format with dots
    Example: general.openstack.image_name
    """
    with open(yfile, encoding='utf-8') as yfd:
        file_yaml = yaml.safe_load(yfd)
    value = file_yaml
    for element in parameter.split("."):
        value = value.get(element)
        if value is None:
            raise ValueError(f"The parameter {parameter} is not defined in"
                             f" {yfile}")
    return value