def oct_to_decimal(oct_string: str) -> int:

"""

Convert a octal value to its decimal equivalent

>>> oct_to_decimal("12")

10

>>> oct_to_decimal(" 12 ")

10

>>> oct_to_decimal("-45")

-37

>>> oct_to_decimal("2-0Fm")

ValueError: Non-octal value was passed to the function

>>> oct_to_decimal("")

ValueError: Empty string value was passed to the function

>>> oct_to_decimal("19")

ValueError: Non-octal value was passed to the function

"""

oct_string = str(oct_string).strip()

if not oct_string:

raise ValueError("Empty string was passed to the function")

is_negative = oct_string[0] == "-"

if is_negative:

oct_string = oct_string[1:]

if not all(0 <= int(char) <= 7 for char in oct_string):

raise ValueError("Non-octal value was passed to the function")

decimal_number = 0

for char in oct_string:

decimal_number = 8 * decimal_number + int(char)

if is_negative:

decimal_number = -decimal_number

return decimal_number

if __name__ == "__main__":

from doctest import testmod

testmod()