Function convert_pressure

Convert pressure from one unit to another. This function accepts both `PressureUnit` enums and string identifiers. # Arguments `value` - The numerical value to convert `from_unit` - The unit to convert from (can be a `PressureUnit` enum or a string) `to_unit` - The unit to convert to (can be a `PressureUnit` enum or a string) # Returns The converted value, or an error if the unit is invalid

(value: f64, from_unit: F, to_unit: T)