def get_attr_info(key, convention, normalized):
    """Get information about the MMD fields.

    Input
    =====
    key: str
        MMD element to check
    convention: str
        e.g., acdd or acdd_ext
    normalized: dict
        a normalized version of the mmd_elements dict (keys are, e.g.,
        'personnel>organisation>acdd' or
        'personnel>organisation>separator')

    Returns
    =======
    required: int
        if it is required
    repetition: str ('yes' or 'no')
        if repetition is allowed
    repetition_str: str
        a longer string representation for use in the DMH (basically
        a comment)
    separator: str
        sign for separating elements that can be repeated (e.g., ','
        or ';')
    default:
        a default value elements that are required but missing in the
        netcdf file
    """
    max_occurs_key = key.replace(convention, 'maxOccurs')
    if max_occurs_key in normalized.keys():
        max_occurs = normalized[max_occurs_key]
    else:
        max_occurs = ''
    repetition_allowed = 'yes' if max_occurs not in ['0', '1'] else 'no'
    min_occurs_key = key.replace(convention, 'minOccurs')
    if min_occurs_key in normalized.keys():
        required = int(normalized[min_occurs_key])
    else:
        required = 0
    separator_key = key.replace(convention, 'separator')
    if separator_key in normalized.keys():
        separator = normalized[separator_key]
    else:
        separator = ''
    default_key = key.replace(convention, 'default')
    if default_key in normalized.keys():
        default = normalized[default_key]
    else:
        default = ''
    repetition_key = key.replace(convention, 'repetition')
    if repetition_key in normalized.keys():
        repetition_str = normalized[repetition_key]
    else:
        repetition_str = ''
    return required, repetition_allowed, repetition_str, separator, default