A bit of tinkering...

python_tinkering.py

# This is the Original Code.
# list(map(lambda x: chr(int(x***2)), [8.54, 10.5, 10.72, 10.6, 10.25, 10.68, 10.04, 10, 7.07, 6.93, 7, 7.35))

# Our first iteration was this:
# list(map(lambda x: chr(int(x**2)), [8.54, 10.5, 10.72, 10.6, 10.25, 10.68, 10.04, 10, 7.07, 6.93, 7, 7.35]))
# which produced -> ['H', 'n', 'r', 'p', 'i', 'r', 'd', 'd', '1', '0', '1', '6']

# It almost looks like it ends with '2016' so we try rounding before casting

# Here's the last 4 items out of the x**2 part:
# [49.9849, 48.024899999999995, 49, 54.022499999999994]
# If we round off everything, we'll have [50, 48, 49, 54] which is '2016' after casting. 

# list(map(lambda x: chr(int(round(x**2))), [8.54, 10.5, 10.72, 10.6, 10.25, 10.68, 10.04, 10, 7.07, 6.93, 7, 7.35]))
# -> ['I', 'n', 's', 'p', 'i', 'r', 'e', 'd', '2', '0', '1', '6']

# List cast is not necessary
the_message = map(lambda x: chr(int(round(x**2))), (8.54, 10.5, 10.72, 10.6, 10.25, 10.68, 10.04, 10, 7.07, 6.93, 7, 7.35))

print ("Message: {}".format("".join(the_message)))