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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def parsedeglat (latstr):
 """Parse a latitude formatted as sexagesimal degrees into an angle. This function converts a textual representation of a latitude, measured in degrees, into a floating point value measured in radians. The format of *latstr* is very limited: it may not have leading or trailing whitespace, and the components of the sexagesimal representation must be separated by colons. The input must therefore resemble something like ``"-00:12:34.5"``. A :exc:`ValueError` will be raised if the input does not resemble this template. Latitudes greater than 90 or less than -90 degrees are not allowed. """

    deg = _parsesexagesimal (latstr, 'latitude', True)
    if abs (deg) > 90:
        raise ValueError ('illegal latitude specification: ' + latstr)
    return deg * D2R