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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 platform_detect():
 """Detect if running on the Raspberry Pi or Beaglebone Black and return the platform type. Will return RASPBERRY_PI, BEAGLEBONE_BLACK, or UNKNOWN."""

    # Handle Raspberry Pi
    pi = pi_version()
    if pi is not None:
        return RASPBERRY_PI

    # Handle Beaglebone Black
    # TODO: Check the Beaglebone Black /proc/cpuinfo value instead of reading
    # the platform.
    plat = platform.platform()
    if plat.lower().find('armv7l-with-debian') > -1:
        return BEAGLEBONE_BLACK
    elif plat.lower().find('armv7l-with-ubuntu') > -1:
        return BEAGLEBONE_BLACK
    elif plat.lower().find('armv7l-with-glibc2.4') > -1:
        return BEAGLEBONE_BLACK
    elif plat.lower().find('armv7l-with-arch') > -1:
        return BEAGLEBONE_BLACK

    # Couldn't figure out the platform, just return unknown.
    return UNKNOWN