def remove_blank_chars(text):
    """
    (str) -> str
    Removes superfluous blank characters from text, leaving at most
    a single space behind where there was more than one (space or newline)
    
    >>> remove_blank_chars('Happy    \n   \n Birthday')
    "Happy Birthday"

    :param text: text from which to remove superfluous blanks
    :returns: text with superfluous blanks removed
    """
    text = text.replace('\n', ' ')
    while '  ' in text:
        text = text.replace('  ', ' ')
    return text