def re_space_out(t):
    """
    Given an input string, return a regular expression that matches any 
    sequence of the characters in the input text, separated by arbitrary 
    number of white spaces in between, e.g.:

    r'\\foo' ==> r'\\s*\\\\\\s*f\\s*o\\s*o\\s*'
    which would match:
    r'  \\  fo  o  '

    'a\\tb' ==> '\\\\s*a\\\\s*\\t\\\\s*b\\\\s*'
    which would match:
    ' \\t\\n  a\\r\\t\\v b  \\n '

    """
    return '\\s*'.join([''] + list(t) + [''])
