def read(self, reg_addr, len_read):
    '\n        read len_read bytes starting from register reg_addr\n        :param reg_addr: (str) register address to read in hex\n        :param len_read: (int) number of bytes to read\n        :return: bytestring of data\n        '
    assert (len_read < 256), 'num of bytes to read cannot exceed 255'
    hex_reg_addr = enforce_hex(reg_addr)
    try:
        req_url = ('%sread/%s/%s/%d' % (self.url, self.dev_addr, hex_reg_addr, len_read))
        resp = requests.get(url=req_url)
        return binascii.a2b_hex(resp.content)
    except ValueError:
        print('i2c failed read')
read len_read bytes starting from register reg_addr
:param reg_addr: (str) register address to read in hex
:param len_read: (int) number of bytes to read
:return: bytestring of data
def read(self, reg_addr, len_read):
    '\n        read len_read bytes starting from register reg_addr\n        :param reg_addr: (str) register address to read in hex\n        :param len_read: (int) number of bytes to read\n        :return: bytestring of data\n        '
    assert (len_read < 256), 'num of bytes to read cannot exceed 255'
    hex_reg_addr = enforce_hex(reg_addr)
    try:
        req_url = ('%sread/%s/%s/%d' % (self.url, self.dev_addr, hex_reg_addr, len_read))
        resp = requests.get(url=req_url)
        return binascii.a2b_hex(resp.content)
    except ValueError:
        print('i2c failed read')