<human>:  Python code to 3 rounding or floats.
<bot>: Here is a Python code to 3 rounding or floats

import math

def round_to_3_decimals(number):
  """Rounds a number to 3 decimals"""
  return round(number, 3)

# Enter the number
number = 12.3456789

# Calling the function
print((round_to_3_decimals(number)))

#Example Output
# 12.346

#Remember to inspect code for bugs.